Materials: DK weight yarn.

Materials note - if you buy two balls of yarn and make the child's size pattern with them, with 8 pattern repeats in the leg, you will have more than enough left over for the toddler size.

Needles: 2 #5 circular needles, or size needed to obtain gauge.

Gauge - 5 to 6 stitches per inch.

The instep stitches stay on one needle throughout, and the heel stitches on the other.

Cast on 35 stitches loosely. Move 17 stitches to the second needle. Join, being careful not to twist the cast-on round. Work 6 rounds of K3, p2 ribbing. Then work one round of *K1, p4; rep from * around.

Pattern rounds:
Rnd 1: *K4, p1; rep from * around.
Rnd 2: *K3, p2; rep from * around.
Rnd 3: *K2, p3; rep from * around.
Rnd 4: *K1, p4; rep from * around.

Repeat the pattern rounds 4 times. End on a K1, p4 row.

Knit one row plain. Make sure your first needle has 18 stitches, your second needle 17. Do your heel flap on the 18 stitches on the first needle.

Row 1:
Sl 1 purlwise, * K1, Sl 1 knitwise; repeat from * until last stitch, K1.
Row 2:
Sl 1 purlwise, p16, K1

Repeat above 2 rows 9 times, for a total of 18 rows.

Turning the heel:
Row 1: Sl 1, k10, ssk, k1, turn
Row 2: Sl1, p5, p2tog, p1, turn
Row 3: Sl1, k6, ssk, k1, turn
Row 4: Sl1, p7, p2tog, p1, turn
Row 5: Sl1, k8, ssk, k1, turn
Row 6: Sl1, p9, p2tog, p1, turn
Row 7: Sl1, k11, ssk

Picking up Gusset stitches:

With the same needle, pick up 9 or 10 stitches along the side of the heel flap. Pick up one more stitch in the intersection where the heel flap meets the instep stitches, to prevent a hole.

Switch to the instep needle, knit across.

WPick up one stitch where the heel flap meets the instep. Then pick up 9 or 10 stitches along that side of the heel flap.

(Yes, at this point you will have many stitches on that needle. It is a bit tricky at first, but gets easier quickly)

Gusset:

Knit across the heel stitches and the other gusset stitches to the last stitch, which you'd picked up in the intersection. Knit it twisted.

Knit next round on the instep needle.

Heel needle, knit the first stitch twisted, knit to center.

Your gusset rounds now start from here.
Round 1 - knit to last 3 stitches of heel needle, K2tog, K1. Instep needle, knit. Heel needle, K1, SSK, knit to center/marker.
Round 2 - K all sts.
Continue this until the heel needle has 18 stitches on it.

Foot:

For the foot, knit stockinette for 6-8 rows or for desired length.

Toe:

Knit all stitches. Again, the round 'starts' at the middle of the heel needle, use a marker if need be. Knit 8 stitches across the heel needle to the center, K2tog.

Round 1 - knit to last 3 stitches of heel needle, K2tog, K1. Instep needle, K1, SSK, knit to last 3 stitches, K2tog, K1. Heel needle, K1, SSK, knit to center/marker.

Round 2 - K all sts.

Continue this until there are 9 stitches left on each needle. Knit one round. Knit to the end of the heel needle. Slip the 4 sts closest to the needle ends over their adjacent neighbors. Use the kitchener stitch to join the remaining 7 instep stitches to the remaining 7 heel stitches.