https://www.newschoolers.com/web/content/pictures/id/113243/member_id/85575/
Heres one i built. it worked good, i put on two layers thin plywood and the HDPE, i didn't use a coping, but because of that it was hard to spin off of, i would use 1/2 inch pvc for a coping if you want coping, but it might be hard to attach