This versatile set of 12 translucent plastic geometric solids uses many of the standard dimensions of Pattern Blocks (sold separately) as each piece's base. Removable lids allow children to compare volume using wet or dry material for concrete, hands-on learning. Includes six prisms (rectangular, square, cube, small triangular, large triangular and hexagonal) and one sphere, hemisphere, cylinder, cone, square pyramid and triangular pyramid each.