UK terms!
Start with standard granny with no chs between. Four rows -

1. Start in corner sp - 3 tr in sp, sk nxt shell, into next & each sp to corner sp (1 tr, 1 dtr into centre tr in prev row, 1 tr), into corners (3 tr, 2 ch, 3 tr). End last cnr - 3 tr in sp, 1 ch, 1dc into top of first st/turning ch.
2. Turn & work on wrong side - In first corner sp, 2 tr, 1 tr in ea tr to corner sp, (2 tr, 2 ch, 2 tr). End in first cnr sp with 2 tr, 1 ch, 1 dc in top of first st.
3. In corner sp, 3 tr, sk 2 tr, between 2nd & 3rd trs (tr, htr worked into the bottom part of that tr, tr in same sp) - reduces bulk so row stays more solid, sk 3 tr. Work from to last 2 tr. Sk those & into cnr sps (3 tr, 2 ch, 3 tr). End in first cnr sp (3 tr, 1 ch, dc into top of first st).
4. Regular granny. Repeat the four rows.