I have made six of these rugs. I didn't starch or press the rounds and they all are flat. I used a bigger zig zag stitch then the pattern said. Also I think the type of batting is key. I used the Katahdin on a roll. The ones in a class where I made my first one, who cut their own strips had trouble with wavy or bowl shaped rugs, maybe they used different batting then what the Katahdin is. The pattern isn't necessary. It doesn't have any special secrets.