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. 
Brother punchcard machines do not advance pattern rows when two carriages are used for needle selection as each carriage begins to move from the opposite side, the same preselection is repeated. This means editing is required at times if the same designs are to be used on electronic machines, particularly true in lace combination fabrics. The process has been discussed in posts on automating lace edgings with slip stitch settings.
this is how the yarn is laid over those 2 needles after the first tuck row is completed, 
and both when using the card and in the first electronic repeat there will be a third tuck loop that is laid over the needle holding the 3 stitches. This is the appearance of the stitch formations just prior to an all-knit row 
Here analyzing the actions of the punchcard, marking rows according to card actions, the repeat is expanded to include the extra duplicate rows. Though the repeat remains 24 stitches wide, it is no longer usable for use on a punchcard machine. 
Tiling the repeats to imagine the final knit presents the problem that results from working on a square grid and comparing the results to a knit, which usually produces a rectangular one. The representation for the linear patterns produced on the knit side of the piece cannot factor in some of the added distortions created by the stitch type used. I process my images in Pages or Numbers, depending on which document contains my most recent work and happens to be open. It is also possible to perform the final rescale in Gimp. Most knits approach a 4:3 ratio, with gauge variants in highly textured fabrics. To preserve a clean design, tile and save the original, screengrab the resulting image, load it in Gimp, and rescale. Repeat the motif for the same number in both height and width when tiling it. 
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, requires color-reverse. Since it is 24 stitches wide and it may also be modified and used on a card. In this instance, the original marks for rows and stitches are single height. The image is processed, matching the original, rendered double-height, color reversed, and then alternate pairs of rows were color inverted to render the repeat used in the test swatch 
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, could also be executed in tuck stitch, which would both widen and shorten the fabric and make the purl side more interesting. The software can provide a preview of the result far more quickly than knitting samples, but again, the previews are only approximations of the scale, and cannot show distortions to lines as one adds more texture.
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
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. A new working repeat: 
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 
Working out an electronic repeat: the punchcard repeat is on the bottom, the expanded electronic one on top, yellow cells highlight rows with tuck stitches 
In electronic machines, the first preselection row may be done with the knit carriage moving from left to right or the lace carriage moving from right to left, with either carriage moving toward its usual starting position. The knit carriage is set to KCI for end needle selection. Before the LC begins to move from the left the first and last needle will have been preselected, push them back to the B position. Continue to do the same if any end needles are selected just prior to a transfer row as you continue to knit. Each carriage makes 4 passes throughout the piece. The bottom row of eyelets shows the “standard” size eyelets that follow single transfers, illustrating the change in size with this technique. With the proper tension, transferring is not a problem. I sampled on a random number of stitches. For cleaner edges, a border where no transfers occur for 2-3 stitches can be planned in programming the final piece.
Returning to Volume 4, here is a combination of lace and tuck repeat that appealed to me. I am repeating a process akin to that used in programming the 
The actions of the 2 carriages on the electronic, the repeat prior to mirroring 
mirrored for use on the 930 
The texture is more apparent on the purl side, the top and bottom edges could be coaxed into a wavy shape due to the gathering up of the knit by the tuck diamond shapes 
Alternative settings for one color pile: Tech 256, back lock FX and both arrow keys, pushers one up, one down, front bed to LX, drop stitches every 2 rows.
the loops, formed on every needle on both beds with the move to the left 
anchored in place on the ribber needles as the only the ribber knits as it returns to the right 
while the carriage is on the right, drop all stitches on the main bed, 
making certain no loops are stuck on gate pegs on the main bed, 
Knitting was smoother with a change in yarn. An extra needle on each side of the knit on the ribber is brought out to hold manually to ensure their stitches knit with every pass of the ribber carriage. I prefer the all-over pile with its loops formed on the top bed. There were nearly no incidences of loops catching on gate pegs on the main bed. One of the drawbacks is that the main bed needles need to be dropped and brought back to the B position manually, bald spots will result where any needles are not returned to the proper work position, so they will not pick up loops. 
and this is likely my last try at the single pile in a pattern using every other needle tuck on the ribber with the release of stitches every 4 rows. I actually like the elongated stitches in the ground but found the stitches planned for loops simply did not release easily or at all, 
Generally when creating these patterns on Brother machines, patterning selection varies for each pairs of rows. I got distracted while making the above swatch by a phone call, got to the point where there is a very obvious solid black all knit row in the repeat, but “forgot” its presence. I assumed I was having a selection or a carriage issue and scrapped the knitting off. Note to self: “remember to always check the programmed design before you do that again in the future”.
a planned color change on the next row would require needles that had been skipped, marked in red, being pre-selected forward for knitting back toward the color changer and returning to the previous or next planned color selection 
Remember that punchcards knit the image as viewed on the purl side of the fabric, so to match any swatch photos given in published pattern books, the exact repeat unless it is perfectly symmetrical, will usually need to be mirrored horizontally for use in electronic machines.
tiling to check the alignment of the 8X10 repeat. 
other possibilities using checks rather than solid lines 
When evaluating published repeats, keep in mind the basics; these are suitable for electronic KMs that will allow for color reverse 
punchcard knitters would have to punch white squares, resulting in this arrangement 
The knit side is not necessarily always interesting. With knit stripes in a different color breaking up the textured segments a secondary pattern will begin to emerge. A closer look at the samples below reveals one repeat is actually the other, drawn double length. This is an easy option, even in punch card machines. When knitting long pieces especially, however, I prefer not to use double-length built-in features, finding it easier to sort out where I am in terms of design rows if errors occur. 
Depending on your machine ie Passap Duo requires 40 stitches punched repeats or modifying for electronics, vertical black columns or additional white squares may be added to the original design repeat units. The corresponding cells are filled with the color gray 
I have begun including .pngs with some of my posts. Check that your import method does not automatically change the mode to RGB. It is a common problem with such grabs from FB. If that happens, index the image to B/W and save it again before using it in download to KM software.
From long design studio inspiration swatches: the secondary shapes are created by varying the number of rows in the color change rotation and placement, the bottom swatch shows the purl side of part of the completed length. Float counts can help duplicate the repeat or color placements if notes are skipped during knitting. 
Working with multiple slip stitch “bars”: this shows my punchcard, marked with color changes once the final rotation was decided, remembering to begin markings 7 rows up from the bottom for Brother (5 for Studio). 
This design produces a fabric that is fairly flat on both sides: the .png is in the same orientation as the punchcard repeat, which you can see is produced with shapes reversed on the knit side in the swatches below it. Instructions on how the repeat was converted to .bmp for download using Gimp in
The working chart, along with an effort to visualize the location of possible color changes in order to create secondary patterns. Color changing on “wrong rows” or starting preselection from the left rather than the right will result in random, not necessarily successful designs 
This swatch segment illustrates the possibility of removing the slipped stitches from the needle bed and bringing them to the purl side, rehanging them on the same needles, bringing all needles out to hold before executing the next all knit row. The “floats” at the bottom of the swatch are from threads that were missed and not brought to the back of the slipped stitches 
Reducing the number of slipped rows 
reducing columns to produce a trim, being certain as to placement on the needle bed 
This repeat produces a ruched fabric when no all knit rows are included, and a sort of “honeycomb” effect when additional color changes on all knit rows are added. The first long swatch 
Shifting slip stitch units to form shapes
If the slip stitch units begin and end with the same color knitting just before them and immediately after, the color carried on the knit side will be consistent throughout. 
A sure way to get the shapes to match your design is to assign a number matching the number sequence in the color changer for your machine to each of the yarn colors. Imagining the results in a spreadsheet or even graph paper 
Expanding each section to 8 rows, the repeat now becomes 64 rows high and allows for 3 colors to show behind the slipped stitches in the chart on the left. On the right, the color-changing order shifts to 6 rows at a time in sequences 1,2,3,2,1,2,3. Design row 1 would begin the piece using the color red, the last row in the repeat is blue, shifting the color then carried up the front of the piece to blue. 
Once the basics are understood, changes in scale and amount of ruched textures along with fiber content are easier to execute 
The chart for the sample below is 30 stitches wide by 84 rows high, and is shown turned counterclockwise 
This fabric has a more compressed shape, the blocks of slipped stitches are in a vertical arrangement directly above each other. A possible building unit for similar structures: 
An all-knit border on either edge will automatically create a ruffle on each side.
The 24X20 repeat for the swatch on the above right, with the floats easily identified on the purl side of the swatch 
Since the knit carriage needs to move to and from the left-hand side of the machine with each color change, an even number of rows in each repeating segment is recommended, but not necessarily required. The first preselection row is generally moving from right to left. End needle selection on helps the edge stitches knit. At times end needles will need to be pushed forward to knitting position by hand. Depending on how the repeat is placed on the needle bed, with some experience with a tuck or slip stitch, one can decide whether keeping the end stitches in the pattern creates a better effect at vertical edges. Analyzing 2 random repeats 
The respective .bmps
As with all punchcards, the first and last 2 pairs or rows are not part of the design, they are necessary for the punchcard to roll continuously in the drum. Keep in mind that the card is reading design row one while your eye sees the row marked #1 by the factory on the card outside of the machine. Following the suggested color changes to match the specific swatch takes the guesswork out of the equation. In DIY or in trying a different color sequence, such guides may have to be shifted and marked accordingly. Specific color suggestions are given in the samples above in the left-hand columns. In #327 the order is in a variable sequence, which requires a bit more attention than #328. Follow the line below the #1 mark to the left, each card begins with color 1. Color notations in 328 are also next to those 2 all punched rows at the top. That is because those 2 rows overlap the first 2 design rows as the ends of the card are clipped together, front over back, for smooth, continuous, advancing movement. In 327 the sequence at the bottom would need to be hand-marked.
Four tucked rows is probably the limit on Brother machines unless one is working in fine yarns. In the first interpretation, the ground knits for 2 rows on all preselected needles. In the second, the surrounds of the interior striping knit for single rows only at the top and bottom of the repeat. Electronic repeats A and B on the right may be as small as a single 4X12 unit.
the “corrected” repeat without additional rows, some possible color changes can follow the colored chart suggestions 
Moving on to electronics, playing with symmetry the repeat now becomes 30 stitches wide, the tiled image check for the unaltered version on the left. 
Tuck knit in a solid color 
Slip stitch in all variations has purl side edges which curl to a greater degree, the short skipped areas were probably due to too tight tension of too quick a carriage pass to the opposite side 
slip stitch with the addition of a third color in the rotation 
The associated punchcard: 
Brother yarn changers are numbered, from right to left, and their published card designs color suggestions reflect that. The lace extension rail must be used as the knit carriage needs to clear the color changer on that side in order for the colors to change properly. 
Some of the Studio punchcard pattern books showed both sides of the expected fabric assi\ociated with each card, here is a repeat that breaks the tuck rule of no more than one blank square side by side in any row.
This swatch pattern from a Japanese magazine illustrates the difference in the formation of the tucked loops when two blank squares exist side by side. The repeat is 10X22, colors are assigned letters rather than numbers here as well 
Another rule breaker: odd numbers of tucked rows with no added all knit rows. Experimenting with such repeats results in less organized all-over patterns, here colors are changed every 2 rows, 
These repeats take shapes in another direction which becomes more textural and interesting when blank stitch areas are expanded for use in slip stitch setting 
This pattern, with color changes every 2 rows and two-row tuck sequences has an assumed interesting pattern shift. 
The tiled X2 horizontal repeats lined up side by side show that extra knit stitches have been added, shifting tuck stitch rows by one stitch in alternating directions, but just because it is published, it does not necessarily make the repeat correct. Those striped areas can only occur if there are solid all punched areas. 
Keeping the constraints of a 24 stitch repeat, reducing the width of segments to 12 stitches rather than 24, the original repeat as amended 
The tiled results for each
An approach to designing such patterns can begin with a template for color changing every 2 rows and taking colored squares away to indicate stitches that will be slipped or tucked.
Japanese magazine publications often recommended many color changes, each for varied numbers of rows. Sometimes more is less. The number of colors may be reduced, and changing the numbers of rows used for each color as well can expand the number of fabrics produced from a single repeat. Good note keeping is a necessity if the intent is to easily reproduce the fabric at a later time.
Adapting punchcard designs for use in electronics becomes easier once one is familiar with the stitch structure. This is a cousin of 328, 13 stitches X 52 rows. Tiling as in all designs helps sort out errors or missing pixels.
and slip stitch changing colors alternately every 2 rows, then every 4: 
My blog posts on working with and designing mosaics (suitable for tuck and slip) and mazes (slip stitch only, multiple side by side unpunched holes or white squares in any row), in reverse historical order
while in slip stitch the strand of yarn bypasses the non-selected needles as the row is knit, forming floats between stitches 
Symbols commonly used for both
Some of the options: 
and not often used, but worth exploring, the use of opposing tuck and slip buttons at the same time. 
As with any knitting, for needle selection to occur the knit carriage (also known as KC) needs to engage the belt using the change knob set to KC. End needle selection or not depends on the goal fabric. If KC is in use but no cam buttons are pushed in, there will be needle selection, but the fabric produced will remain stocking stitch.
Converting the cards to black and white pixels: the small single repeats for each card are highlighted with a red border. Depending on the method for programming the electronic machine, however, the single repeat may have to be repeated horizontally to match the number of stitches to be used in the piece. The third repeat is a hybrid of the previous 2, the start of making what is published more personal 
The blank vertical areas may be arranged moving across the repeat’s canvas in a variety of ways. In this chart the tuck symbol is evident, some of the knit stitches around each tuck series are highlighted at the bottom of the chart in green, the single electronic possible repeat is 4 sts by 12 rows 
Few tuck stitches amidst lots of plain knitting are likely to not distort the fabric very much or produce a noticeable texture. The fabric will lie fairly flat, and approach a width proportionately closer to that of stocking stitch using the same yarn. The outlines can serve as markers for the introduction of additional hand techniques ie tying objects or beads in the center of the shapes after knitting and prior to felting in order to obtain surface bubbles of non felted stitches, or marking areas for duplicate-stitch or other embellishments.
With the basic structure recognized, weaving punchcards may be suitable, not all need be color reversed. 
251 is a bit more problematic. Half the repeat is wider than 24 stitches. Here it is readjusted to 24 stitches, the height is 32 rows which may just barely squeak by punched only once 
the repeat is tiled to check proper alignments 
This repeat is from a Studio mylar sheet. It also may be used in punchcard machines after removing 2 columns, since only half the repeat is necessary, and it is 26 stitches in width. The color reverse option is necessary. In electronic machines, it is easily accomplished with a command or the flip of a switch/ push of a button. The white squares as given would produce loops on all the corresponding needles, with no stitch formation in those areas. 
I chose to eliminate 2 columns from the blocks on the left. Tiling shows the amended repeat’s appearance, with the color reversed image for actual knitting to its the right. 
Repeats with a balanced number of black and white squares provide all-over textures in fairly balanced fabrics. As the number of black squares on a field of speckled tuck stitches grows, the knit shapes may actually poke out from the surface of the knit, since those areas are not gathered in the same way as their surroundings. Yarn properties and tension also have an effect.
tiled 42X62
Designing your own can begin with the choice of a template, such as this one, 24 stitches by 36 rows. 
Working with a different shape, using copy and paste to place it, adding a brick variation on the right, for punchcard full repeats of 24X40
The matching electronic repeats for both, unless your download requires programming for the total number of needles in use:
Testing tuck stitch limits, breaking the side by side white square rule in all over patterning with moving blocks of 2 by 2 blank squares 
