I have a big spool of bungee cord I bought for a project; I needed two feet, and it came in a 50' length. Amazing the number of tasks it gets put to! I used a king sized sheet because I buy big white flat sheets at Goodwill for use as muslins and sewing tests. This was the nicest one I had on hand. I made the pattern by flipping the board upside down on butcher paper and tracing around it, then adding an inch to every edge. I would add at least two inches and plan to cut down if I were doing it again; probably would have if I had watched through Leah's video before starting!