Thorndike’s Puzzle Box Shown here is one of Thorndike’s puzzle boxes, which were made mostly out of wood slats and wire mesh. Thorndike constructed a total of 15 different puzzle boxes, which varied in how difficult they were for a cat to escape from. In a simple box like this one, a cat merely had to step on a treadle at the front of the cage to escape. More complex boxes required the cat to perform a chain of three responses—step on a treadle, pull on a string, and push a bar up or down (Chance, 1999).