Fisher-Price Rock-a-Stack and Baby's 1st Blocks Bundle Rock-a-Stack toy lets baby sort & stack the five colorful rings, then bat at the wobbly rocker base to discover what happens Stacking rings on the base from biggest to smallest helps baby understand the concept of relative size Babys First Blocks offer put & take play, as well as stacking, sorting and matching to help baby develop problem-solving skills Grasping & sorting help baby develop finger & hand dexterity Placing blocks in bucket helps strengthen eye-hand coordination