MindWare KEVA Contraptions Reactions Planks Building Toy – 178 KEVA Building Planks (191 Piece Set) – Free-Form Wood Building Set for Kids to Create Their Own Ball Maze – Ages 7 & Up

From the brand

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)