THROWWith larger hook, ch 146 to measure 45 inches.
Row 1 Sc in 2nd ch from hook, * ch 5, skip 3 ch, sc in next sc; repeat from * across (36 ch-5 loops made). Ch 5, turn.
Row 2 * Sc in center ch of next ch-5 loop, work 8 dc over next loop, sc in center ch of next loop, ch 5, repeat from * across to last loop, ch 2, dc in last sc. Ch 1, turn.
Row 3 Sc in first dc, * then dc in first dc of next 8-dc group, (ch 3 and slip st in 3rd ch from hook for picot, dc in next dc of same group) 7 times (shell made), sc in center of next loop; repeat from *. Ch 8, turn.
Row 4 * Sc in 3rd picot of shell, ch 5, skip 1 picot, sc in next picot of same shell, ch 5, dc in next sc between shells, ch 5, repeat from * across, ending last repeat with ch 5, dc in last sc. Ch 5, turn. Repeat Rows 2-4 for pattern until piece measures about 62 inches from beg, ending with a Row 3 of pattern. Do not fasten off.
With smaller hook and spacing sts to keep edge smooth and flat, work a row of sc along side edge, across bottom (working into unworked loops of foundation chain) and along remaining side edge, working 3 sc at each corner. Fasten off.