XL Polydron pieces are 4 times the size of Giant Polydron! Designed to fit perfectly with existing Giant Polydron, this set teaches children concepts of 2D to 3D construction. This 24 piece set will allow you to build towers, rockets and larger constructions. Children will love to build towers and look through the windows in the triangles and squares. Suitable for age 2 . Teacher's guide included.