Tangram an ancient Chinese game. Rearrange the 7 tiles to make new shapes. Such as faces, animals, emojis, houses, geometric etc. The rules are that all tiles must be used in the pattern and must be touching.
Found an old book on the subject and looked up the subject online. The tiles can be made by paper folding and cutting or by calculating. You can see that the large square is made from three different size triangles one square and one parallelogram. Each tile is coloured differently.