Abstract: A plane jigsaw puzzle has multiple plastic pieces with concavo-convex structures on side edges, where the plastic puzzle pieces are matched and connected to concavo-convex structures. A chamfer angle is set at the edge between pieces, and the height of the chamfer angle to the edge interface of the two adjacent pieces is from 5% to 50%. The contact area of the two opposite adjacent pieces is 95% to 50% of the contact area of the corresponding edges.

Abstract: A picture mosaic's foldable piece and frame are present. The picture mosaic's piece has the first piece and the second piece, and one side of the first piece is connected with one side of the second piece by a strip connector, and the first piece can fold backward or forward from 0 to 180 degree relative to the second piece along the connector, and shape projections or concaves are set on at least part of the other sides of the first piece and the second piece to connect with other pieces. The picture mosaic's frame comprises at least two picture frames connected by strip connectors, and anyone of the picture frames can fold backward or forward from 0 to 180 degree relative to the adjacent picture frames along the connectors, and shape projections or concaves are set on inner sides of the picture frames to connect with picture mosaic's pieces.