Used Building Dexterity cog gears toy kids 3+ Hands On Learning. Experiencing problem solving while in play. These are colorful plastic gears cogs used for a cause and effect strategy. Parts are built on each other by pushing two parts together. Match up the cogs on the gears and snap on to vertical pieces. They can lay down on the base or be built up on more bases. Turn one by hand and they all move. Such fun. One cog has an inner circle snapped. See photo.