Wooden Block Logical Thinking Combination Module Puzzle - Blue1. Easy first, then difficult, step by step, the difficulty of game cards gradually rises, and the difficulty of 30 game cards is subdivided, allowing children to gradually build self confidence. 2. The edges of the exquisite solid wood are smooth, without burrs, and the edges are rounded to make the contact more assured. Harmless environmentally friendly water based paint. The color is soft and not easy to fade. The thickness of the wood block is