Through Pattern Blocks, kids develop an understanding of geometry, shape, symmetry, tessellation, angles, measurement (perimeter and area), algebra (patterns), and numbers (fractions). Set includes 120 transparent, plastic pieces in 6 pattern block shapes and colors: orange square, blue rhombus, red trapezoid, green triangle, yellow hexagon and clear narrow rhombus. Pieces feature raised edges that are easy to pick up. Packaged in a jar with lid and carry handle.