IN PROGRESS
The companion post Single bed slip stitch vs ruching explores automated textures that could share design repeats.
Gathering knits to produce folds rather than clustered stitches can be achieved by using programmed slip stitch designs, or manually lifting stitches from rows below the last row knit in an endless variety of ways.
Hand-gathered stitch groups, in proportion to their numbers, produce a hem that is sealed more tightly than the slip stitch versions, whereas the skipped stitches become elongated.
Machine-knit hems 2 illustrates multiple techniques for picking up stitches, ie. by first finding sinker loops
Select few stitches lifted up on a tuck ground: Pretend/ mock cables 4 
Ruching 1: fern “pretender” and more, a charted repeat that moves sinker loop groups, a technique that begins to imitate smocking.
Randomly selected samples from former posts:
Ruching 2: more working with stitch groups
Shadow pleats knitting 
Adding hems to varied knits includes this knit woven sample
Color striping, “winging it”, in New single bed swatches based on random sources of inspiration 
Manipulating slip stitch floats Slip stitch patterns with hand transferred stitches, single bed 2 
Industry knit stitch vocabularies refer to the yarn portion that connects two adjacent needle loops in the same course/ row as a sinker loop, 
making what is often called a ladder in home knitting, an extended sinker loop. 
The spreadsheet plan aided by some copy and paste is to count down to specific ladders, and use their loops to rehang on specific needles after every 10 rows knit in a brick stitch configuration.
The vertical blocks of stitches between out of work needles that produce the ladders are 9 stitches wide.
A single full repeat is 20X20, the test is knit on 55 stitches, with 2-stitch borders added aside first and last ladders.
Counting down sinker loops 
rehanging 5 times on the left side
repeating 5 times on the opposite, right side, with 2 extended loops now on the center needle of the 9-stitch group
what can happen when one is so busy looking at and manipulating stitches as to forget to look up. 
An alternate method is to count down to specific sinker loops, magenta, then manipulating the knit loop aside the last one lifted,
or seek out the adjacent sinker loop, cyan, and pick up the one immediately below it, magenta.
In the test swatch, to maintain an easy row count, stitches were lifted up in a brick configuration after every 10 knit rows, on 38 needles, a multiple of 6+2, that included an added single knit stitch vertical border on each side.
All-knit rows can be added in each half repeat block, cells representing them are colored in darker grey. The single design repeat is 12X28, 14 rows are knit before ruching, and pick up starts with the 6th sinker loop down.
A side-by-side comparison 
This repeat is 16X42 pixels and may be used color-reversed for a slip stitch variation.
Here, ruching/ pleating happens with lifting stitches for 5-row folds after every 6 rows knit followed by 2 all knit rows, making each pattern full block 7 rows in height.
Whether lifting stitches or changing colors, the carriage will not stop consistently on the same side as each block of lifted stitches is completed.
If color changes are planned, changing the folded depth to 6 rows from 5 will make the use of the color changer possible and avoid extra yarn ends.
The yarns used in the test swatch were a 3/9 wool and a sock yarn remnant, knit at tension 10, resulting in a rather stiff knit. Individual stitches were lifted on each edge aside the large all-knit segments to avoid ruffling and attempt at a balanced length.
Spacing the ruched segments further apart and increasing their width may make lifting every other stitch adequate for the 3D desired effect.
In this 75 stitch wide test, each of the 7 stitches in the black blocks was rehung on row 9, followed by 10 knit rows for easy tracking, and the process was repeated in brick fashion in the allotted locations. 
Some double bed work:
Pintucks 2, ripples in knits using the ribber includes this Passap sample 
Pintucks 1 vs shadow pleats