Ch. 21, turn.
r1: Sc across, 3rd loop. Ch 1, turn. (20)
r2-42: 2sc in 1st st, blo sc across, 2 sc last st. Ch. 1, turn.

r43-60 (18 rows): blo sc across, ch 1, turn.

Piece should be approx 12”

Turn piece, Work (hdc, ch1, sk1) evenly up side. These “holes” can be used to lace the back straps to achieve and individual fit.

At top corner, sc, ch 227, sk 2 (for tassel in end loop created), sl st back down chain (this is the first strap). Sc in same st. Sc across top to last st. In last st, sc, ch 227, sk 2, sl st back down chain, sc in same st (2nd strap).

Continue down 2nd side of top, as for first side (hdc, sk 1, ch1). Do not finish off! Turn work to bottom edge.

Bottom trim:
You might have to fudge a bit to get the stitch count to work. I usually wing the trim design.

Sc in 1st st, ch 2, sk 2, v-st. in next (dc, ch 2, dc), ch 2, sc Repeat across. Ch 1, turn.

Sc in 1st sc, ch 2, (in center of v-st) 2dc, ch 3, sc in 3rd loop {picot made}, 2 dc, ch 2, sc in next sc across. Finish off, weave in end.

Lace top in the back as for shoelaces, criss-cross, ending at the bottom (see pic).