I hook & cotton yarn
Ch 5, join with a slip stitch.
*3 dc in lp, 2 ch*; Repeat * to * 4 times ; slip stitch to first dc.
*(3dc, 2ch, 3 dc) = corner in next sp, 1 ch*; Repeat * to * 4 times ; join with slip st.
Ch 1, sc in every dc around, working 3 sc in every corner.