Design and Build Amazon Moving Machines In a chain reaction, one thing leads to another, which leads to another, which leads to another, which. ..well, you get the idea. With the stuff in this kit and a pile of your own ordinary LEGO bricks, you can build Ten awesome machines that can be combined to make dozens of different chain reactions that use many steps to do. ..a whole lot of nothing (or maybe something vaguely useful). Your machine could toss a gum wrapper into the trash, amuse your dog, deliver a message ('Oh Yeah!'), ring a bell, and generally make you the envy of the neighborhood. WARNING: CHOKING HAZARD - Small Parts. Not for children under 3yrs. CHOKING HAZARD - Toy contains a marble. Not for children under 3 yrs. CHOKING HAZARD - Toy contains a small ball. Not for children under 3 yrs.