Forts fall down. BUILDIES is a system of interlocking blocks and "mortar" that lets kids build sturdy constructions. Studies show playing with blocks helps kids develop their spatial, mathematical, & problem solving skills. Experience shows kids love playing with cardboard boxes. We think kids should be doing a little less screen-swiping and a lot more building & creative play! With BUILDIES, kids learn about engineering, physics, & architecture while they play.