Tangrams http://www.mathematische-basteleien.de/tangrams.htm
tangram facts
Proof by Fu Traing Wang and Chuan-Chih Hsiung in 1942 (Book 4) Grid Tangrams with
tangram facts
Proof by Fu Traing Wang and Chuan-Chih Hsiung in 1942 (Book 4) Grid Tangrams with
Eine Übersicht über das Tangram-Puzzle
Beweis durch Fu Traing Wang und Chuan-Chih Hsiung 1942 (Buch 4) Gitternetz-Tangrams