[STEM Toys That Teach: These KEVA blocks help kids gain first-hand experience with balance leverage geometry and the principles of physics while fostering an interest in architecture and design Create Chain Reactions: Use the wooden building planks to build a marble run full of tunnels ramps and other contraptions then see if your KEVA ball sets off chain reactions like knocking over a bowling pin or ringing a bell Unique Plank Building Block Set: This wood building set features traditional KEVA planks along with colored building planks and unique pieces to create one-of-a-kind KEVA ball run structures No Hassle: These premium KEVA STEM planks are precision-cut from beautiful wood to stack perfectly time after time no glue or connectors needed; simply unpack and build impressive KEVA structures KEVA Contraptions Reactions includes 178 wooden planks for building 8 dowels 2 reaction balls 1 bell 1 string 1 bowling pin 1 toy car and a 16-page illustrated idea book (Ages 7 and up)]