I used a size 6 crochet hook and size 10 crochet thread. It is slightly less than 1/4" wide. About 1/2" overall.
I simply made my chain. Then turn, and sc in second chain from hook. Then sc in next 2 chains. Now do 2 more sc in the same space as that third sc. You will have 3 sc in same chain.
Now sc in next 2 chains. Then skip next 2 chains, and sc in next. Sc in next 2 chains. Now for the top peak again, do 2 more sc in same space as last sc.
Basically, to form your peaks you will have 3 sc in one chain, then to form the valleys you skip two chains and sc in the next. Cute Huh?