For foundation row, crochet 27 chain.
Into 2nd chain from hook, one chain.
Next row: 3 chain, 1 chain into second chain from hook, 3 chain (repeat to the end of the row) Turn
Repeat for 27 inches and cast off.
Fold one side over (see video)
Fold over other side.
Sew or crochet together (see video)