3Otters 3D wooden puzzles are very challenging to work with~ Each set contains 3 different patterns of 3D wooden puzzles. A ship, Jeep, and helicopter~ Materials are made of wood. Each piece is precut with number on the side to identify. Remove carefully from the wood sheet and use the enclosed sand paper to sand down the edges to avoid splinters if any. Follow the diagram sheet to begin assemble plane, boat and car. Might require adult supervisions on assembling the whole unit together. Once done assembling, each model can be painted over with your favorite colors. It's very challenging to assemble each one of the item, but once completed, feeling accomplished~ Teaches hands/eyes coordinations too~