Guidecraft Rainbow Blocks Set - 10 Pcs. Kids Learning & Educational Toys, Stacking Blocks Solid wood frames with inset colored acrylic windows for ages 2+ Set includes 4 rectangle, 2 square, 2 triangle and 2 half circle shapes Standard unit block measurements Material: Hardwood frames with primary colored, transparent acrylic windows Educational Focus: Visual perception, mathematical skills or light table activities with STEM applications