CubicFun 3D Puzzle S-Series "Double Decker Bus" A fun and challenging 3D puzzle of a London Double Decker Bus Constructed using CubicFun's unique slotting system Difficulty Level: 2 stars ; Number of Pieces: 66 Construction time: 50 to 60 minutes Length when completed: 19.7cm Push-fit 3d puzzle with durable materials, easy to assemble Colorful assembly instruction with background knowledge of the architecture Assemble with patience and carefulness, do not force to interlock any two pieces/components. Every puzzle pieces have two sides, and can be bended into only one direction, please make sure the correct side of the pieces are faced outward. Assemble every section of the model without any tools, such as knife, and scissors, neither as gluing. Follow the instructions on the booklet to build your puzzle. Each puzzle piece is numbered to help you complete the assembly. Punching out all the interlocking holes before assembly is adviced. To make sure every pieces can be clearly identified, do not pop out all pieces at once, please only detach those pieces you need for each step during the assembly (as pieces numbers are all printed on the puzzle sheet next to every puzzle pieces).