Tangram consists of three kinds of figures. It includes five isosceles right triangles (two small triangles, one middle triangle and two large triangles), a square and a parallelogram.

Characteristics of jigsaw puzzles

Tangram is very entertaining. As the above ballad says, this seven pieces of paper or wood chips composed of a square, five triangles and a parallelogram, as well as the plastic jigsaw puzzle, also contain many interesting mathematical problems, which are fascinating.

In contrast, although there are hundreds of small irregular puzzles sold in shopping malls at present, besides patiently killing time, how can a regular jigsaw puzzle with only seven pieces like Tangram let players give full play to their imagination and creativity?