Cast on 16 stitches, using a provisional cast on. (After finishing the sock, you'll join the toe sts with Kitchener stitch.)
Divide sts onto 4 needles, being careful not to twist the row, and join. Knit two rounds, then work increases as follows:
Rnd 1: On needle1 and needle 3, knit across to the last 2 sts on the needle, increase 1 st by knitting into the st below the next st, knit 2 (to finish the needle). On needles2 and 4, knit 2, inc 1 st by knitting into the st below the st just knitted, knit across.
Rnd 2: Knit around
Continue these 2 rnds until there are 14 sts per needle.
[for the one I just started, I didn't do rnd 2 until I'd done two increases, so I had six sts per needle]
Instep: Knit foot to 2" less than the desired length from tip of toe to back of heel. Knit to the end of N3 and stop.
Row1: (right side) Knit all the sts from N4 and N1 onto one needle and turn - 28 sts. You are now ready to knit back and for. (At this point, I like to put the sts from N2 and N3 onto waste yarn, b/c if I don't do that, I pull the sts at the corner of the heel every time I turn the row and it leaves a large st which looks like a hole when I continue knitting the instep.)
Row2: (wrong side) Yarn over, p28.
Row3: Yo, knit across to the last 2 sts and turn, leaving those 2 sts on the left needle. They will look like a tight pair. Continue in this manner. On each successive row, begin with a yo and purl or knit up to a tight pair and turn. This leaves an increasing number of pairs on the needles. When you finish the ninth pair on the right side row, purl back and prepare to turn the heel.
Turn the heel:
Row1 (rs): Yo, knit across to the first pair and knit the first st of the pair, turn.
Row2 (ws): Yo, purl across to the first pair and purl the first st of the pair, turn.
Row3 (rs): Yo, knit across to the yo from the previous row. There will be 2 yos on the left needle, then a row of pairs. Slip the 2 yos and the first st of the next pair kwise and return them to the left needle. K3tog, turn.
Row4 (ws): Yo, purl across to the yo from the previous row. Slip 2 yos and the first st of the next pair pwise and replace them onto the left needle. P3tog, turn.
Repeat rows 3 and 4 until all but one pair on each side have been knitted.
Return to working around:
Replace the sts that have been held on waste yarn to their respective needles. There should be 14 sts on each.
Rnd 1 (rs): yo, knit to center back.
Rnd 2: On N1, knit across to the last 2 sts. They should be 2 yos from the preceding row. Sl them knwise, then sl the first st from N2 kwise and return all 3 sts onto N2. On n2, k3tog, then knit across. On N3, knit across to the last st. Sl that st and the first 2 sts on N4 (which should be yos), return them to N4 and k3tog with N3. Otherwise there will be 13 sts remaining on N3 and 15 on N4. You'll see when you knit it. On N4, knit across. There should now be 14 sts on each needle. Double-check this and adjust if necessary.
Knit until leg measures desired length.
Work k1, p1 ribbing for 1 1/2"
Top edge: Finish with invisible bind off.