Guidecraft Sensory Rainbow BlocksAn adventure in color, light and sound! Encourage sensory exploration by combining blocks to form new colors and sounds, or stack the blocks in a different order each time to form new and exciting shapes. Shimmering water, sand and crystal bead interiors enhance visual stimulation in block builds. Smooth hard wood frames with plexi windows. Sized to standard unit block measurements. 18 block assorted shapes set. Features Solid wood frames with inset