Here again, half fisherman or full fisherman rib is be used. The zig-zag happens at the top and bottom of the fabric. In half fisherman, the setup is once again for full needle rib. If knitting in one color the sequence is: knit one row, rack a space, knit one row, rack back again (X and Y below represent the 2 racking positions involved
for 2 color fisherman, the sequence is knit 2 rows with col 1, rack one space, knit 2 rows with color 2, rack one space back again
this fabric is produced in conjunction with a pattern repeat using the principle that black squares knit (pushers up, needles preselected), white squares tuck (pushers down, needles not selected), the repeat is 12 stitches wide, 2 rows high; it is possible to have 6 stitches tucking side by side because this is an every needle rib, and there will be a knit stitch on the opposite bed anchoring down each tuck loop
This type of repeat became popular in Passap clubs for use in their Passap ripple afghan. The racking first to the left and knit a row, knit to the right and knit a row, was interrupted after 36 rows, followed by a color change and a no-racking knit row before resuming the previous racking sequences.
When single or multiple odd # of rows with no racking are introduced at intervals the zigzags once again happen at sides rather than top or bottom, with the knitting after the no racking row(s) reversing direction. The yarn used in these swatches is a random acrylic, presses flat, not the best if aiming for any 3D textures; the color difference is due to photos being taken at different times of day
what happens when multiple odd numbers of rows are knit changing back lock set to N (all knit), no tuck stitches. The fabric still swings in opposite directions, and in addition, the all knit rows produce areas that “poke out”, beginning to create scales of sorts
it is a matter of personal preference whether the extra effort with full fisherman rib is worth any difference in appearance or result in the final fabrics. Changes in tension, yarn fiber content, and machines used add to the variables. Good notes in trials help one determine predictable results and to choose whether the effort may be worth it or not. Using laborious techniques for borders rather than whole items is always an option.
1/22/2016: half fisherman racked rib knit in thinner yarn, wider # of stitches and more rows in pattern group before single N/N row, no blocking