Construct a variety of contraptions without the need for glue, screws, or staples! Each kit contains plywood panels with all the necessary pieces to make each machine. Pieces can easily be punched out, then fit together to build various machines. Picture instructions are included for assembly and each piece is numbered to help determine placement. When pieces are assembled correctly, they will fall into place with a satisfying “click”. If the builder desires to personalize the gadgets, they can also be painted. Having assembled similar models, I recommend having a toothpick or like-sized metal tool on hand to punch out very fine or complex pieces, and sandpaper for the rare times a piece requires edges to be smooth. It’s great fun to construct these mechanisms and see them clipping along without any electrical parts! Once the projects have been completed, they have moving parts for interactive play. Some models are even powered by rubber bands! ~ Janine