Slippers on two needles (ankle socks)

Pehorskaya Yarn No. 16/2 (780 m) cone 4P14 in 3 threads. The sole - in 4 threads. The calculation is given for size 39. You can change the size by increasing/decreasing the number of cast-on stitches. The rest is knitted without changes. On the 7 central stitches of the toe part, you can make a pattern in the form of holes or braids.

Cast on 67 stitches on circular needles. Knit 4 rows in 1x1 ribbing.
5th row: 1-edge stitch, 29-knit, yarn over, 7-knit, yarn over, 29-knit, 1-edge stitch.
6th row and all even rows are knitted purl.
7th row and all odd rows are knitted knit, making yarn overs before and after the 7 central stitches.
Knit until there are 40 stitches on both sides of the central 7 stitches (including edge stitches) = 20 rows

We knit the sole on 13 central stitches. We knit 37 knit stitches (counting the edge), then knit 12 stitches knit, knit the 13th and 14th together. Turn the work to the purl side, knit 12 purl stitches, knit the 13th and 14th together. And so on... That is, knit like the heel of socks.

Knit until there are 13 stitches left on the needles.
This is how it looks from above

and from below:

We knit the heel. For this, we put on the needle the extreme walls of the edge stitches of the left side. We knit 12 knit stitches, knit the 13th and 14th stitches together.

Turn the work to the purl side. Put on the needle the extreme walls of the edge stitches of the right side. Knit 12 purl stitches, knit the 13th and 14th together.

Continue knitting until there are 13 stitches left on the needle. Close the stitches.
Here is what we have achieved: