Learning Resources Gears! Gears! Gears! Gears! Gears! Gears! Treadmobiles Building Set. There are so many ways to build and play with this fun construction set. Children follow along with the included build designs and use colourful gears and rubber treads to build basic machines that turn, twist, and move. The engineering fun doesnt end there children can also build their own creations, and even add more gears from other Gears! Gears! Gears! sets. Features multilingual packaging and build guide. The smallest gear in the set measures 6cm in diameter. 108 Piece Set.