The 15-Tangram Book & Puzzle

This beautiful kit of tangram includes 15 pieces made of wood and an illustrated guide of instructions. In the first chapter of this guide there are explained different geometric basic forms. Once you have learnt these concepts, players can try to solve the jigsaws. At the end of the book you will find de solutions. 

This tangram is special, because it has 15 pieces instead of 7. It was invented by Tong Yegeng, a Chinese scholar who lost his oficial title and turn into a hermit. Tong Yegeng called this puzzle "diagrams that improve intelligence.