I decided to make my slippers with stockinette stitch on the foot and heel stitch on the heel, to get a similar effect to what I was seeing on the originals. That’s how this pattern is written. It wasn’t until I had almost finished the second slipper that I realized what technique was actually used on the originals. The fabric is, indeed, stockinette stitch, but although it is a single color, it’s worked with two strands of yarn and every other stitch is knit with each strand. My slippers are not made this way, but if you would like your slippers to have this thicker, double-stranded fabric, simply add a second strand of the Main Color after you work the first few rounds of the toe, change to the larger needles, and work the remaining stockinette stitch sections as follows: (K1 with Strand 1; k1 with Strand 2) around.

You can also continue this pattern on the heel section, working the garter stitch borders using both strands held together. Working the center in stockinette stitch with alternating strands is more difficult when working back and forth and purling with 2 strands on the wrong-side rows, so you can also switch to a single strand and heel stitch if you prefer. The colorwork design across the top of the foot transitions to a different design on the sole.