7-st RPC Sl 4 sts to cn and hold to back, k3, then p1, k3 from cn.
7-st LPC Sl 3 sts to cn and hold to front, k3, p1, then k3 from cn.

(worked over 23 sts)
Rows 1, 3, 5, 7, 9 and 11 (RS) K3, [p1, k3] 5 times.
Row 2 and all WS rows [P3, k1] 5 times, p3.
Rows 13 and 29 [K3, p1] twice, 7-st RPC, [p1, k3] twice.
Rows 15, 19, 23 and 27 K3, [p1, k3] 5 times.
Rows 17 and 25 K3, p1, [7-st LPC, p1] twice, k3.
Row 21 7-st RPC, [p1, 7-st RPC] twice.
Row 30 [P3, k1] 5 times, p3.
Rep rows 1-30.