Contraption is a unique, motorized game from Lakeside. The game itself consists of 2 sets of colored marbles and a single unit with 4 gears on its surface. The gears are laid end-to-end, with the larger gears in the middle. Each player claims one of the smaller end gears as their 'home' gear.To play, the unit (requiring 2 'D' batteries) is turned on, which sets all 4 gears spinning. Then the marbles are dumped into the large central gears. Each player controls a switch that, when pressed, lowers a gate between their home gear and the larger gear, allowing marbles to pass through -- but also letting marbles pass back out to the larger gears.The goal of the game is to be the first player to capture all 6 of your marbles in your home gear. - BoardGameGeek