The base of the catapult I made holds the whole structure and keeps the cork and the spoon form flying off some where. The base is made up of two sheets of 1 mm thick cardboard. The cardboard should be cut up into two rectangular pieces of cardboard a little bigger than an index card. The size of my base is six inches long and 3 inches wide. After you have your two cardboard pieces you should put glue (I used hot glue) on one of the cardboard pieces and smash 'em together and wait for the glue to dry.