Interlock is produced commercially on special circular machines and some double system flatbed knitting machines. The patent for the associated circular machine was applied for in 1907, and a copy may be found in the google patents archive. The stitch originally commonly used cotton, in machines that were able to produce a gauge of 20 stitches per inch, often used in T-shirt knits. As technology expanded so did the possibilities for a wider range of gauge and expanded structures.
I have found references to accordion, fleecy, Piquette, cross mix, and bourrelet interlock versions, enough to make one’s head ache when considering forming them on home knitting machines.
The fabric lies flat, relaxes in width but is fairly stable in height. It has good shape retention, raw or cut edges don’t curl, and it will unravel only from the last row knit. There are many variations including eight-lock, bourrelet, Ponte di Roma, and waffle weaves. Many directions are included in Machine Knitter’s source. Interestingly enough, they are shared in the chapter on knit weaving. The instructions given are for punchcard machines, often accompanied by a hand selection of needles in either or both beds. Hand selection on the ribber is easier to track by having an even number of needles in work on the ribber, bringing the first up on the left, then the first up on the right, so the illustrations for stitch formations are written that way, the selected needles knit. Lili button selection begins with slipping the first stitch, followed by knitting the second stitch on both sides. In most fabrics, as long as the remaining repeat aligns starting with a slip stitch on the ribber does not matter, as the complete repeat is shifted over by a needle. 
The structure can be knit with color changes to produce vertical stripes of various lengths. My initial proofs of concepts are usually in single colors.
In interlock, alternate stitches are knit on each bed, so it takes two complete carriage passes to complete a single row of knitting, making the resulting fabric thicker and heavier, with the same appearance on both sides, making it reversible. Carriage passes need to be distinguished from design rows. Charts indicate both, but not necessarily numbers reflected on mechanical row counters.
The usual rib configuration 
Planning for interlock:
The fabric may be executed on Brother knitting machines by programming 1X1 needle selection on the main bed, with the smallest component bordered in red. The Brother ribbers have a matching needle selection to 
when the lili buttons are used with the machine set to slip in both directions. Studio or Knitmaster knitters would require an RJ1 ribber carriage. I refer to the marks on the Brother ribber needle tape as blanks and dashes. When lili buttons are in use, one must work on an even number of needles. Pairs of both are required. The starting placement on either of the 2 marks does not matter, the first needle on the carriage side on the left will always slip, with the last stitch away from the carriage always being knit. This observable if one “air knits”, slowly moving the ribber carriage from side to side. As in any pattern knitting, needles selected to D or E will knit, the ones lined up in B position will slip or tuck. 
The needle selection needs to be coordinated so that needles opposite each other are not selected at the same time. Since the first needle on the ribber will slip, the first needle used in the pattern preselected on the main bed must be selected forward to knit, and the number of needles in work set up accordingly. Many published illustrations begin patterning from the right. I prefer to do so from the left. My final repeats were planned with needle placement shifted over by one so as to begin with a knit stitch on the top bed, a slip stitch on the ribber due to the fact that the ribber lili selection is fixed to always begin with a slipped stitch. Starting with the carriages beginning on the left side, the first needle in work on the ribber is on the left, the last needle in work on the top bed is on the right, an even number of stitches are in work on each bed. The setup after the first preselection row, with COL: 
Imagining the sequences required to complete a single row of knitting. I prefer to start with a knit stitch on the left, top bed, end needle selection is canceled
When testing new ideas, particularly in rib setups, I often begin on a small number of needles and in a way that feels “safe”. This was my first test, with the ribber set at half-pitch. There is an obvious difference in rib before the slip stitch segment and the every-needle, EN, segment. 
Using a very thin space-dyed cotton, tension 4 on both beds, produced a soft, drapey, squishy fabric. Because once the cast on and needle set up are complete, the knitting occurs on every other needle in alternate directions, full-pitch is used without any problem even though every needle is in use on both beds. 
These fabrics will knit both at half-pitch and full-pitch once the pattern needle selection is established. The difference may not be noticeable depending on yarn choice and tension, or ribs may appear to group together in pairs. Pleating in interlock may be produced by removing needles alternating from each group. The tuck setting may be used in these experiments as well, resulting in additional width.
Pique variants: rows 1 and 2 complete one row of knitting using both beds
row 3 knits on the main bed alone
rows 4 and 5 complete one row of knitting using both beds
row 6 knits on the ribber alone
charting out possible actions and repeat adjustment. 
The rows where only a single bed knits will create long stitches due to their being skipped on the opposite bed. Reversing and alternating the selections make the fabric reversible. The tricky part would be canceling out lili action on the ribber every 6 rows when the top bed alone needs to knit, row 3 in the design repeat. To accomplish this, after row 3 is preselected with the carriage on the left by releasing the ribber carriage, lean it forward so it will not engage any needles in work on the ribber resulting in dropped stitches, and moving it to the opposite side of the machine. One can actually get into a rhythm doing this. 
As the knit carriage moves from left to right, only the main bed needle selection will knit. When the KC reaches the right, engage the ribber carriage, and knit until the same design row is reached. The blank row at the top of the 6-row repeat automates and allows for the carriages to knit from right to left on the ribber only, again creating some long stitches on skipped needles.
The selection continues to be EON after proper needle set up, so the full pitch setting is used once again prior to continuing in the pattern. 
This is an instance of cast-on and bind-off edges that will tend to be pulled a bit wider than the remaining knit. Depending on the final use for the fabric, that may or may not be a consideration.
I usually begin with tentative charts in a spreadsheet to consider what components may be automated and what might be the most advantageous selection of patterns on the main bed. At this point, my solution for no stitches knitting on the ribber for single rows remains to knit the carriage forward and remove it from the equation for that row.
Swiss pique or overknit is a half-pitch fabric. It looks like French pique but is a little narrower. Looking at completed knit rows, identifying the top bed patterning, isolating patterning selections 
carriage passes required 
The ribber here knits in one direction, slips in the other. The first preselection row is made toward the color changer, needle set up is checked as for previous samples, the ribber is set to knit to the right, slip to the left 
the appearance of the stitches when both carriages knit 
after only the top bed knits with slip stitch floats behind every skipped stitch, which, in turn, will appear longer on the knit face
Ponte di Roma
the modified version of the repeat used in my test swatch
Pairs of rows of interlock are followed by pairs of circular rows. The repeat was changed and the second color was used to define the difference in stitch formation between the two groups, color changes were made every four rows. 
Using a single pair of carriages and having to constantly change cam settings appears far too complicated to manage for producing any length of fabric. My hack for making things easier and faster was to resort to knitting with 4 carriages. One pair was set for interlock operating from the left, the other set so as to achieve tubular knit. The ribber carriage is set to knit from right to left and to slip from left to right when the main bed knits. The knit carriage is set to slip in both directions so that the pattern selection remains continuous. It will slip all stitches while moving to the left on rows with no needle preselection, knit on all preselected needles on its return to the right.
Extension rails are used since both KCs are selecting patterns. I wrote about the concept of using 4 carriages in 2019, in the Geometric shapes on ribber fabrics with tuck stitches: knitting with 4 carriages post. The difference here is that the carriages on the left do not have the added benefit of support from the color changer. The elastics placed as shown may have been more for my psychological well-being than for the continued proper function of machine parts. There is a limit to the width of knitting that may be produced this way with the carriages coupled on each end. The knit carriages may travel off the top bed and onto the extension rails safely, but the ribber carriages must remain anchored enough on the rear rail so as not to go flying off on their own while clearing the end of the belt on each side. 
I prefer leaving the slide lever in the center position in all my rib knitting and am not convinced as to a visible difference between knitting at half or full pitch in the swatches with the yarns I have used so far.
Bourrelet is characterized by horizontal relief ridges on one side, is made with an interlocking base, is sometimes referred to as ottoman rib or ripple stitch, is sometimes referred to as Evermonte, is knitted at half-pitch. The combined carriages knit for 4 rows, followed by four rows knitting on the top bed alone.
Seeking a workaround other than disengaging ribber carriage or canceling lili selection and leaving the carriage on the slip setting in both directions on rows where only the top bed knits, one option to speed up the process is to hack a main bed sinker plate. The result is the ability to use a second knit carriage to select and knit patterns on the top bed only, operating from the opposite side. Four passes on either bed complete 2 rows of knitting. The post on ribber fabrics produced with 2 knit carriages selecting needles describes the process in more detail. 
To use the yarn from the right, only before the first carriage pass to the left, its end needs to be knit through a stitch on that side to anchor it. A different cone or ball of the same color and weight yarn may be used, or in my case, I used a thin, different fiber in a second color.
The swatch was knit in four-row sequences, there is a subtle ridge apparent on the knit side created when only its rows knit, which could easily have enhanced by knitting more rows on the single bed. 
In eight lock hand selection is required on the ribber, the technique reminds one of the double-faced aka reverse jacquard fabrics. 
My initial test was to knit twice as wide a repeat, thinking it might be easier to identify stitch formation, working on 4 X an odd number of stitches, in this case, 36, beginning and ending with knitting on the top bed, 
but 1: I actually cast on 34. In a swatch, such adjustments 2: are easy to make. The only automated selection of needles on the ribber is EON using lili buttons, in any other configuration there is no choice but to hand-select needles in between selected needles on the main bed. Casting on at half-pitch begins with the first needle in work on the top bed, the last in work on the ribber. Once the first row has been preselected, and the pitch is changed to P the ribber moves to the left, leaving an even number of needles in work opposite each other on both beds. Both carriages are set to slip in both directions. The knit carriage will knit the automatically selected needles, slip the unselected, while the ribber knits needles brought up manually to D position, skips the remaining ones in B.
A 2X2 needle selection tool for a 9 mm machine or a 7 prong transfer tool may be adjusted and used to help bring up the proper needles to E position on the ribber. 
single row pockets are formed. 
Even though the needles are in full pitch, if an error in needle selection 3: happens across a row a tip-off will be that floats are created on the main bed between selected needles, and there will be a textural change across the row of knitting unless the error is corrected.
If another yarn end or a second color is added, as always, check and make certain the first few stitches knit. Proper lighting and using a yarn color and thickness that can actually be distinguished on the needle bed are useful to avoid 4: dropped stitches not being noticed. The color change 5: shows that a single row is indeed completed with every 2 passes of the carriages, and there is a shift visually in the linear pattern. 
The same process could be applied to the charted repeat. A needle selector can speed up the manual work on the ribber for 2X2 selection 
Tuck variations: tuck, cross tuck, royal, texi plique. So far these are my tentative charts for the stitches, each pair of rows represents a full single row of knitting. There are situations where cam settings would require changing from slip to tuck and some locations where the same needle selection repeats on subsequent rows, leaving lots to ponder about and proof, my starting charts are often edited and at times abandoned as the work progresses and both eyeballs and brain have had a break. In this instance, the topic will be reviewed again in a future post. 
Since most of my swatches are experiments and I work by trial and error, I am now rethinking my repeats and reached the what am I doing? point.
I have some interesting or even pretty fabric swatches so far. Illustrations in published sources are often shown for interlock fabrics on every other needle, my supposition has been that with every needle in use on both beds, at half-pitch placing the needles on one bed in the center of those on the other and working in thin yarns the same repeats would work for achieving knits in these families, so in my illustrations, the symbols are placed to represent needles in work between each other on alternate beds, rather than truly on every other needle. To review, the differences between pattern selection using the slip or the tuck setting: with every needle in work on the ribber, the repeat 
is programmed on the top bed with the first preselection row from right to left, the needle setup, depending on the starting and ending needles used. 
With both part buttons pushed in, in every needle rib, the needles in D will knit, the ones in B get skipped completely. As the carriage passes to the right, the needles for the next row are preselected, come forward holding only the skipped stitches in the row just knit, while the alternate needles are set up to be skipped on the next pass to the left 
After the two passes one full row of knitting is completed on the patterning bed. The needle preselection is now on the next row of the repeat, in this case, row 1.
Tuck setting using the same repeat behaves differently. With both tuck buttons engaged, by default, the needle on either side of the tuck stitch will knit, with every carriage pass. The starting preselection is the same as for the slip stitch version, after the first pass to the right, the preselected needles to D will have been knit, with tuck loops formed on the previously non-selected needles. Because the repeat alters needle positions every row, as the right side of the bed is reached, the tuck loops from row one will appear on the shank of the newly preselected to D position needles, ready to be knit, and the alternate group of needles is held back to create the next row of tuck loops as the carriages return to the left. 
The process repeats throughout. Two passes complete a single row of knitting. The carriage actions for completed passes 1 and 2 
The result is a very pliable fabric that when relaxed off the machine and stretched shows the tuck structure more, is reversible. The basic repeat elongated on the top bed creates a vertical striped pattern if color changes are added, coordinated with needle selections, and are made every 2 rows. As an experiment, the double-length patterning was tried at the top of the swatch. At that point, the fabric is no longer reversible unless the 1X1 fixed needle selection is altered manually on the ribber. My yarn is thin, and the tension used on the loose side. 
The close-up begins to make the tuck loops a bit more visible. The swatch was knit at half-pitch. Using full pitch in patterns that allow for it, diminishes the appearance of “ladders” between rows of stitches, indicated by cyan arrows. 
More basics: on the ribber, whether using lili buttons or not, these are the lever and change knob positions available 
Manually the tucking lever position can be changed from R to P for a single row or more of tucks and then returned to the R placement. Switching between the 2 stitch types on the ribber is far easier and less complicated than changing cam buttons on the main bed, however, there are no rows where only tucked loops are created without knit stitches beside each of them if the lili buttons are in use. Using the slip-tuck Brother selection on the main bed allows for slip and tuck settings to be used at the same time in the same row as long as opposite cam buttons are in use. Some of the old punchcard books include patterns referred to as “lace-like” using the setting. The starting side makes a difference in results as to whether one leads with a slip stitch float or a tuck loop in the actual knitting. Swatches in this post have begun with the first needle in work on the ribber and a forward, to be knit, stitch selection on the first needle on the top bed, with an even number in work on both beds. The end needle selection is canceled unless stated otherwise. The cam setting used for these tests 
the setup row with the first preselection row knit from the right, ending COL 
as the carriage moves back to the right, the previously not selected needles will slip and get a tad longer while being preselected forward to D for the next carriage pass. Once the pass is completed, the needle selection has reversed, the now non-selected needles will tuck as those same needles are preselected for the next pass from the right.
The appearance COR 
After the return pass to the left, the tuck loops are evident on top of the needles preselected forward to knitting position on the next pass to the right. Two carriage passes fill one row of knitting, here ending COL. 
On the ribber, as seen in the thumbnails, one may choose slip or tuck in one direction alternating with an all knit row in the other, or tuck or slip in both directions in an alternating pattern EON_EOR, on an even number of needles with the addition of lili buttons. The appearance on the ribber of the formation of the loops echoes that seen on the main bed changing needle placement unless the carriage is set to tuck in only one direction. 
A variant of the single bed capability for changing stitch type formation with direction may be achieved on the ribber by manually changing the tucking lever from R to P when the other side of the knitting is reached. 
A test can quickly be made to observe the stitch formation with the main bed set to knit every row. I chose the left tucking lever down to R when the carriages were on the left, up to P when the carriages reached the right. The tuck stitches with no further action line up over the knit stitches in the previous row 
There often are aaargh moments in knitting. This has happened to me with some 7 prong transfer tools before, here it did with a double eye tool on my transfer row prior to binding off. There must be a split in the eye of the tools not visible to the human eye resulting in the stitch entering the eye. So far I have been able to rescue the stitches involved, but not without lots of fiddling and some cursing 
Experiments outside the interlock family: the two-by-two repeat is supplied in most packets of cards that come with the purchase of a punchcard machine. At one point in time, Kate Armitage published a book containing 104 variations of knitting using the card, both single bed and combined with ribber use. There was also the equivalent for card #3, the point being variations are limited only by time and imagination. 
Because I am now completing posts over time online as opposed to working offline and then publishing, the opportunity is there to share mistakes as well as what appear to be successes at the moment. Once again I fell into the not-writing notes because it is so obvious mode and there was enough time lapse between my first knit swatch below and my writing about it that I was no longer certain about the settings used when sharing it. The knit has more stretch and texture than seen in the photo 
Re-swatching for possible variations, with notes this time and with lili buttons in use. If the cams are not in the up position on the ribber carriage, stitches will knit, not slip. N is king, without cam buttons in use in either bed, stitches will knit even if a pattern is being selected. There is an adequate stretch at the top allowing the fabric to relax achieved by transferring to the main bed and using a latch tool bind off around 2 gate pegs. The possible variations are endless, note to self: remember to keep good notes. 
The colored versions before and after scaling, compared with the slip-stitch swatch. 
It is possible to produce a rectangular grid to start with on which to draw in Gimp, but the larger canvas size occupies a significantly larger space on the screen, complicating the process. For small designs, however, that may be an option to give one the sense of aspect ratio for the design in the final knit ie in representational FI. To resize the grid in uneven proportions, the chain-link below the spacing values needs to be broken 
This repeat is designed for an electronic, and requires color-reverse.
Once again, the possible change in scale is estimated. The repeat though only 24 stitches wide, is 92 rows high. On the left the repeat is shown as it appears on a square grid, to its right is the scaled 4:3 version, in a pixel count approximating the size of the swatch. It takes a bit of squinting to see the pattern more recognizable in the longer repeat in the larger tile 
The swatch was pressed, becoming wider than when first off the machine. It was knit using the slip stitch setting, which could also be executed in a tuck stitch, and would both widen and shorten the fabric and make the purl side more interesting.
and with a check tuck pattern that may change in aspect ratio considerably when knitted 
The proof of concept swatch, knit in tuck stitch, begins to show the distortion by the stitch formations, textures vs plain knit, easily seen at the top edge. The bind-off is around 2 gate pegs in order to allow enough stretch. 
Anyone familiar with either or both programs may find this a very quick way to visualize the scaling and moving of motifs within DIY designs and their possible outcomes prior to test knitting
As stated, the process is easier and quicker working on non-selected groups. Above, the yellow yarn was thicker than the blue. To maintain proper color selection in the non-selected column, the center needle needs to remain in the B position, with the slipped stitch forming floats below it before the next row knits. If the needle is brought out to E, it will knit in the contrast color, forming floats in that color on the purl side, and a knit stitch in what was planned as an all-solid column on the knit. The results are seen at the top of the first sequence in the swatch. I chose to limit my number of floats to 4 to keep the process manageable, moved stitches on the left of the center needle to the front of the knit, and then followed with those to its right. One of the many things to explore in hand technique fabrics is finding a way to handle tools that may be more comfortable than others, practicing on single blocks of color first can help establish that. Below both yarns are equal in weight and thinner. The floats formed by the color in the B feeder are also hooked up on the center needle in each vertical group in that color, forming a pattern on the purl side as well. 
The needle position for selection for B feeder yarn also needs to be maintained. Bringing the needle out to E ensures it will knit on the next pass. In both of my tests, the slip stitch floats on the knit side lie more horizontally than the lifted-up floats on the purl. 
The video knits each color for an even number of rows. Bring the first and last needle into work on the ribber before knitting each row. The remaining stitches are knit only on the main bed. The knit carriage is set to knit, the ribber to slip in both directions. Pick up the chosen color on the left, and knit for an odd number of rows, when the carriages are on the right, push held needles back to work position so they will knit on the pass back to the color changer. The ribber knits the next color. A review of the Brother ribber carriage for those not familiar with it 
knit for an odd number of rows, with carriages on the right, push held needles back to work position so they will knit on the pass back to the color changer. COL: the knit carriage changes back to knit settings, and the ribber slip setting in both directions is restored. The center stitches that formed ribber butterflies are transferred up to the top bed, and needles at the center of the blank areas on the top bed are brought out to hold. The color is changed, and the process begins again. 
My first efforts were met with dropped stitches after a few rows and expletives. My second effort fared no better, I simply could not avoid dropped stitches on either bed, perhaps because of my yarn choice and the small tension it required. Working on the single bed once more, using the slip stitch setting and knitting one color at a time, I achieved a fabric more similar to the original photograph. The chart reflects the number of needles in my test swatch, with a 2 knit stitch border added on each side 
The transfers in the piece begin on row 5. Before the next row is knit in the alternate color, the slip stitch floats are reconfigured, bringing stitches 1 and 2, 4 and 5 in each group to the knit side of the fabric, leaving the center floats undisturbed. 
Bring the whole group out to the E position so they will form knit stitches with the first row of contrast as the carriage moves to the right. 
The extra needle selection prior to the next all knit row helps track the direction of the moves, stitches are moved three at a time, there are no cable crossings
The next step for me was to explore cable crossings on elongated stitches working double-bed. A basic pattern on any programmable machine for playing with elongated stitches on one bed while knitting every stitch on the other is to program pairs of blank rows followed by solid punched or black pixel rows. The yellow line in this chart illustrates the row on which cabling might occur. 
Programming the width of the needle bed allows for only the stitches forming vertical columns in chosen locations to be put into work, allowing one to place groups that will involve crossings anywhere on the chosen pattern width. A base is knit in the ground color, which slips for 2 rows on the main bed, creating the elongated stitches that will be cabled. I had no problem with 2X2 cables, 
Cabling, returned to in a later post, with adjustments, making things work.
Continuing with shapes on striped grounds, this is the result of a self-drawn pattern 
The approach is different than in the blog post on 
Punchcards, in theory, may be used as given and set to double length, while for use in electronics drawing the pattern single height and using the double-length setting is also an option. Starting sides and fixing errors have always been more confusing for me when using the double-length feature, I prefer to punch holes or program pixels as I intend to knit them. The isolated reduced repeat for use in the electronic is charted, with an initial one-pixel error in 2 consecutive rows, marked with red cells. In transcribing any design, it is worth checking repeats multiple times after eyeballs and brains have had a rest. This was my start:
The design process using Numbers before exporting the repeat to Gimp for reduction to B/W png: in this approach, the repeat is drawn double height to start with. The red cells represent stitches that will be transferred down to the ribber before knitting the next row in the pattern color from left to right. 
The first test is of an isolated motif. The yellow arrow points to the pixel error, the cyan to the positions where some needles in the full repeat were “accidentally” placed in A position, not B, resulting in pattern stitches not being formed. 
Two other options for charting the fabric in numbers: A. draw the repeat as given
Any simple Fair Isle repeat may also be used. The numbering in the charts matches what is normally seen on the left edge of the tables
The world of possibilities grows even further for single color shadow lace, when, examining the same design, one recognizes that the pile knit card, with the blank rows filled in in pattern, is the same as the fair isle version of the repeat, rendered double long 
Some authors have suggested plaiting as an alternative to creating shapes with true brioche, which can be complex. To my mind, plaiting falls in the beauty being in the eye of the beholder category, I prefer far crisper color distinction in my knits. This sample from the previous shadow lace post uses thick and thin yarns 
its accompanying test swatch 
the file for multiple repeats after color reverse 
There is an interesting scale and depth of fold comparison between this version and the first using the repeat, achieved by tightening the tension as much as possible, and possibly by reducing the size of the eyelets. 
Take care if copying and pasting single columns to alter a repeat width that the whole column is indeed copied and that if using the pencil tool flood fill is not used unintentionally. The original intent was also to correct the elongated slip stitch segments on the edge of the programmed vertical designs marked in blue, but the paste with errors in red accomplished creating the same issue 
The first segments were knit using striper backing, with the ribber knitting every stitch, every row, in both colors. When a slip stitch is used with needles out of work on the main bed, end needle selection should be canceled. In A it was not. The result is that end needles alongside the out-of-work column knit with each color in each row. In B, end needle selection was canceled, and one can now see the elongated slipped stitches that result from areas that should have been marked with the contrasting color 
As long as the number of stitches on the ribber is even, lili buttons may be used, affecting the scale of the pattern in both height and width. In A, they were used with the ribber set to slip in both directions, in B, set to tuck in both directions. C marks the return to the N/N setting, with needle transfers to mark a possible pleat. 
The initial pleat idea charted out for single stitch folds, stitches transferred to ribber in the R columns, to the top bed in the T columns 
The result is a fairly soft pleat, the choice below was to retain end needle selection. 
Various ribbed pleat configurations are explored in 
Paired transfers in the planning stages: because the repeat is small and has a single center pivot point, it is rendered once more, adding columns
Here the transfers planned to opposite beds are marked on a 48 stitch repeat with red cells.
The resulting fabric relaxed on the left, lightly steamed on the right 
Note: the color positions in the design have been reversed from those in the first swatch. If “floats” are noted at any time in the spaces where needles are out of work on the ribber, look for dropped stitches.
Needles in locations where only the backing is to be shown are transferred down to the ribber. Leaving the eyelets, they were transferred back up to the main bed when brought into work to reverse or change the shape. Addition and subtraction of stitches take place before the next pass with the alternate color. Here movement is random, to get some sense of the effect, it could be made deliberate by following a chart or color separating and automating the pattern, with its starting side on the right. 
What of having shapes appearing in each of the 2 colors on a striped ground? Eliminating some of the guesswork I used the repeat from a previous single-bed blog post on 
The resulting sample, the yarn is thin, might have benefited from tighter tension and more contrast. 
In terms of positioning the carriage, a wire that is akin to that found on Passap strippers is on its underneath. In positioning the carriage on the beds, check visually that it is indeed lying between the gate pegs of both beds prior to attempting to travel with it to the opposite side 
For my test I used EON needles on the ribber, planned alternating selection for each new transfer. This could be done by selecting dashes and blank spots on needle tape ie. dash in the above photo, blank spaces below 
My first attempt at creating shapes includes a band at the bottom where the EON transfers as above were made, but every row. Simply bringing needles into work on the opposite bed creates an eyelet. They can be eliminated by sharing stitch “bumps” on the opposite bed, but for the moment they are a design feature. The texture created appears in the areas involved on both sides of the knit 
It is possible to transfer single needles at sides of shapes ie 
or whole rows, but the change lever needs to be set to position accordingly.
The enclosed punchcards: 
Transfers of stitch groups, whether by hand or using the accessories are made on rows where no needle preselection occurs on the main bed 
This series is a proof of concept for my approach to developing electronic cues
The original repeats were modified to include 2 blank rows between segments that allow for transfers between beds not hampered by needle preselection on the top bed. The motifs are color reversed, but not the blank rows between them. 
The knit carriage is set to select needles KC I or II, end needle selection does not matter. All needles on the top bed knit every stitch, every row, whether or not those design rows contain black pixels. No cam buttons are pushed in. Blank areas between black ones indicate the number of needles that actually need to pick up loops on the ribber to create shapes, filling in spaces between selected needles until an all-blank row is reached for making transfers. The chart on the far right illustrates a shape where the easiest method becomes one where stitches on the ribber are manually transferred to the top bed in order to reverse the shape and maintain every row preselection. The selected needle corresponding to the black square marked with the top of the red arrows is pushed back, the ribber stitch below is transferred onto it, the needle with the couples stitches is brought to E position, moving across the bed in proper locations prior to knitting the next row. 
In this repeat, the side vertical panels of ribbed stitches are added. The knit stitches on each side of them roll nicely to the purl side, creating what in some fabrics can actually be planned as an edging. 
My takeaway is to test the accessory with some patience, sort out the sweet spot for the ribber needles in relation to main bed ones in terms of handling transfers and yarn thickness, use colors that allow for easy recognition of proper stitch formation, keep good notes, and “go for it”.
In the first sample, equal thickness yarns were used, the colored yarn was a rayon slub with no stretch and slippery nature. 
Cast on for EN or EON rib. Transfer all the main bed stitches down to the ribber. Extra stitches can be cast on and transferred in addition to the planned width of the repeats to create a border on either side of the designs. During patterning there will be stitches in work on both beds at intervals, so the pitch needs to be set to H while knitting. When the top of the piece is reached, transfer all ribber stitches to the main bed and bind off.
If any stitches are pushed all the way back or in mixed alignment during transfers, 
A closer look 
The same repeat may be used to produce a tucked version. In many punchcard machines, a card is supplied with a 2X2 check. With the main color, in a suitable yarn, cast on for 1X1 rib. Set the knit carriage to tuck and the ribber carriage toknit. Knit 2 rows with the contrast color, followed by 2 rows with the main color, repeating for the desired length of the rib. Knit the last row in the main color with both carriages set to knit. Transfer the ribber stitches to the main bed to continue knitting single bed.
The repeat is suitable for punchcard machines as well. The first preselection row is toward the color changer, end needle selection is on. Cable crossings, 1 front, 3 back, are made every 4 rows except where the color reverses at the midpoint, where 4 all knit rows are preselected and occur. The fourth, extra non selected needle, X, is removed on a tool and held in front of the work. The three adjacent stitches are then also removed on a tool, moved to fill in the now empty needle to the left in the bottom segment of the repeat, to the right in the top half. The remaining held stitch is then transferred onto the newly empty needle. All stitches in the transfer group are brought to D, the remaining needles should have been preselected. If any have been disturbed, line them up as well so all the needles will knit with the carriage set to slip. 
The color is changed, and the row with the completed transfers becomes the first all knit row in the next color pair or rows. 
Working on a single bed is for me, more user-friendly than double bed. I like to program the width of my repeats when possible, they can then be treated as single motifs, the default in the 930 with downloads using img2track, and I do not have to rely on notes, memory, or position programming to place the work predictably on the needle bed. My full repeat
The knit carriage was set to KC I and to slip in both directions, the same design and execution methods were used as for the first swatch. The yarn is 2/18 wool, the tension was set at 4.., the slipped and crossed stitches pull the fabric in both width and height, the swatch was steamed and pressed to flatten it. Small eyelets occur along the edges where the single stitches were moved to one side or the other across three needle positions. It was not possible to produce a 3X3 crossing at the center of the shapes. 
Over time I have encountered illustrations of unraveled knit or slipped stitches being brought out to the purl side, creating thread patterns on the knit surface, and changing the color structure on the purl. This illustrates a slip stitch being created via a hand technique 
Here the dropped stitch is hooked up on the purl side 
In testing techniques, a simple design that is recognizable with the preselection of needles makes it easier to track progress and accuracy. Though these patterns may be executed in a single color, working in contrasting, bright yarn colors is helpful in isolating stitch formations and understanding their structures. More than one stitch may be moved at any one time. I found when using more than 2 rows of slip the ground fabric began to look gathered and distorted, so my tests are knit using 2X2 pixel blocks.
push tool back toward the needle bed 
insert a latch tool from behind between the prongs of the multiple eye tool, 
lift the floats over the eyes of the tool, placing them behind it and the slipped stitches, being careful not to hook them up onto gatepegs,
now lift the original slipped stitches back onto their previous place on the needle bed, they will be part of the first all knit row in the contrasting color; 
bring the needles with the restored stitched out to E, thus making certain they will knit as the carriage makes its next pass 
The pattern is charted below in development, color changes were planned every 2 rows. The third blank row in each slip stitch location marks the spot for the above manipulations to take place, noted in the chart with grey cells marked with pink dots. After the initial preselection row toward the color changer, only for the first all knit pattern row, push non-selected needles out to hold, E, to ensure all stitches will knit in the ground color. Subsequently, the first design row is part of the continuing repeat. The next color change will begin to form the floats. 
The sequence at the bottom of the swatch is off because I had a change of heart about which color I wanted to form the solid color shapes 
To my surprise, the process became oddly meditative, and I moved onto a different motif built with 2X2 pixel blocks. As seen with mazes and mosaics, a design intended for standard fair isle, tuck, or slip, with color changes every 2 rows, will produce an altered final shape, 
Combining hand techniques: the starting chart begins to address the movement of stitches. On the left, the placement of crossed colors is shown, but technically the design produced is different. On the rows marked with X and red cells, cable crossings are made. All stitches in that row are then pushed out to E, the color is changed and the result is that row and the preselected next one are going to knit on every stitch, those rows are highlighted with red cells on the right as well. Black cells reflect punched holes or repeat for a 24 stitch brick repeat
Two types of crossings were used in the swatch, one moving the elongated slipped stitches on the knit side of the work, the simpler process, 
A design with each color being crossed: the attempted visualization and repeat. 
The repeat appears to use slip-stitch in a vertical column, not ever possible in standard knitting. The explanation is that on those blank rows, crossings are made prior to knitting the next row. The chart on the left reflects the needle placement of each color after the crossings. All pattern needles are then brought out to E, maintaining the needle selection. Slipped stitches will have been replaced by knit ones in the alternate color.
The charted repeat 
A couple more ways to transfer those slip stitch floats to the front of the fabric: floats can be lifted on top of the needles that formed them and behind the stitches on them, a fine knitting needle or tool can be inserted through the stitches across the row, a few, or a pair at a time, being careful not to twist the stitches. In turn, the stitches can then be dropped off the main bed, held on the needle or tool, and be replaced carefully on the needles in question across the row. Crossings are then made, the proper needle set up is manually chosen for the next carriage pass, and the process starts over again. Folks who like lifelines could thread a ravel cord threaded through a needle and use them to remove the same stitches off the bed instead of the knitting needle. 
The charted repeats are for the red cable with the second spacing, illustrating options for cabling on row 7 or row 11, pulling needles out to E after making the transfers before knitting the last row of the design. Pairs of slipped and all knit rows are added to lengthen the distance between cables and to reduce some of the extra lengths in all striped areas 
This idea may work in a border or a trim as well. I did not test bringing the slipped stitches to the purl side. The chart shows adjustments in the placement of the repeat to make tracking crossings easier 
The actions taken
One more to try 
Another approach is to bring elongated stitches created manually up on the purl side. The resulting fabric will be more gathered on the knit side, with no formation of slip stitch floats, it is referred to as 
Proof of concept: the bottom half is knit using the slip stitch setting, the top half in the tuck setting. The added texture on the tuck stitch purl side makes the fabric a more interesting, reversible one, and wider than its companion. 
For a different way of working with two-color initial images using only Gimp, see tips in 
Numbers processing to ready the repeat for final gimp editing: 
Getting back to clearer pattern results: when using electronics, it is possible to create far wider and taller repeats for download. The technique to achieve them uses the same process. That said, there are quicker ways to attain the final repeat illustrated in the 2024 posts on using Gimp color to alpha through the Layer> Transparency option or Colors> Color to Alpha.
the isolated repeat, double-length 
the color separation in progress
When knit, that white cell pair of rows break up the overall shapes and shifts the pattern in the top and bottom half 
The final adjusted repeat 
knit using the tuck stitch setting in both directions, KCI, first row left to right, leading with the dark color 
and here with the lighter color 
In progress, on the km 
the relaxed, 3D-ish view on the reverse 
why projects can take longer than planned 
The finished, relaxed scarf with pressed edges only, retaining the conical striped forms
The repeat knit double length, changing colors every 2 rows, becomes something quite different, with a sharp curl to the purl side 
with my color changer in this threading sequence throughout
where normally each color in each design row knits twice. Because selection occurs for pairs of rows, the first preselection row is from right to left. To decrease the backing rows, the ribber is set for birdseye. I prefer to have an end needle on each end on the ribber, keeping in mind that the total number of needles in use there needs to be even. The machine provides reminders as to which color should be knitting. My samples are knit using KCI on the top bed. Because the preselection happens twice, it is easy enough to knit in pattern from left to right, 
when the carriages have reached the right side, simply use a ribber comb to push all needles back to B. 
Speeding things up with color separation, beginning with the method that will have each color, each design row knitting twice. The repeat is 10 rows high, so it is expanded X6 to 10 by 60 rows. In the final result, the second row for each color in the separation is in turn erased. The red was added to make all 3 colors visible while working the separation, avoiding confusion with the white ground. The knittable result as usual is in a black and white png 
The img2track settings are for now for 2 color knitting, the prompts for the color changes are lost.
The ribber can also be set to knit every row, resulting in elongation on the knit side, while creating an interesting striper backing
Comparing this version to the birdseye backed one for repeat height 
Comparisons: HoP, pushing back needles to B, and color separation results. In the latter, the design is likely elongated in part due to a change in the distribution of thinner yarns to larger design areas with no tension adjustments 
The Ayab lettering as opposed to numbers move from right to left. The manual states that the color separation order is: white C, grey B, black A with their sequence = C (3), B (2), A(1). If the prompts for changing colors as given are followed it provides a very valuable in tracking them, but if out of habit one knits in the usual 1,2,3 sequence, the color placement occurs in an unexpected order and may result in errors. The on-screen letter prompt corresponding to the anticipated color change sometimes occurs with the knit carriage on the right, sometimes as it approaches the changer, and the size of the font was hard for me to see since the screen was not close enough for easy visibility.
If the png is copied from the post it is likely to appear in RGB mode and it will require conversion to 3 color bitmapped. Its grey color map entry is seen below 
The small file makes for a quick test of proper color selection for each of the three colors used 
Having some idea of stitch counts for each color in the design in the first few rows can help identify proper, planned color placement errors 
My first swatch using the heart of Pluto separation and a greyscale motif 
My tested color change sequence is #1, #2, #3 colors throughout, I disregarded the prompts for color changes at the bottom of the Ayab screen. Some things to ponder: in pieces that require color changes, starting with waste knitting in the same colors can help assess the best tension, whether each color will be picked up properly, and if the colors work well together. Looking at these 3 small tests, it appears that a choice should be made when casting on about using color 1 or 2 for the preselection and cast on rows. If the setting to slip is forgotten for the first move to the left, the color in the feeder will knit every stitch rather than a pattern selection. Always check settings when on the right, making certain lili buttons are set as well. This pattern does not contain 3 colors on every row. In addition to that, when working DBJ with other color separations one is likely used to seeing knit bed needle selections on every row. That is not true here, is a function of the technique, not a patterning error. On rows that have colors missing, when that color is in use, the main bed slips, the ribber works every other needle, first in one direction, then the other, adding to the row count on the purl side of the knit. 
The mess at the bottom was due to the green yarn getting caught on the needle bed and not knitting the necessary stitches on the ribber, so dropped stitches were formed 
The assumption is that if the C, B, A rotation and prompts are to be followed, the middle color 2 can stay in place, and the placement of 1 and 3 can be exchanged.
