@trekster The biggest pumpkin was made out of a 18"X24" 4mm black piece of coroplast. The other two were cut out of pieces that big. I would post a picture of the back, but I broke my camera at Scout camp. I am not sure when I will get another.
@inzeos I printed out a 3/4" grid pattern to help with spacing. I kept every thing square to keep it simple. I marked out my patterns with a pencil until I got what I liked(the kids helped design some of it). Then I drilled holes in the coro with a harbor freight dremel knock off that I bought years ago. There are probably 1001 ways to punch or drill holes into coro. I even read somewhere that one guy melted holes in with a solder iron.