Brackitz Pulley Set for Kids | Building Toy for Boys and Girls Ages 4, 5, 6, 7, 8 Years Old | STEM Discovery Learning Kit | Best Children Educational Construction Toys | 77 Pc SetBrackitz pulleys set allows little engineers to build replicas of real world machines and contraptions to gain a concrete understanding of the principles that make them work. This educational toy has been used in classrooms to demonstrate engineering concepts like resistance, force, motion and mechanical advantage using simple machines. Brackitz award winning building toys are unique in their ability to connect anywhere, at any angle, improving your