Nest, tumble, WOW! Each TumbleRoo features a weighted base for wonderful wobbling, a concave top for nesting, and unique, subtle textures to feel and explore. Nest the smallest inside the other two - The moment you let go, the whole stack tips over and they all tumble apart, one at a time, to rock and wobble around and around. Little ones can't wait to nest and tumble again and again! Wiggly wobbly action is sure to launch the little ones into hours of tactile fascination with TumbleRoos.