See inside how things work An amazing flap book packed with inventions, machines, gadgets and devices, and facts and information about how they work. See inside how things work An amazing flap book packed with inventions, machines, gadgets and devices, and facts and information about how they work. Over 90 flaps reveal the insides of car engines, toilets, escalators, submarines and microwaves and many, many other machines. Includes internet links to websites with animations, games and experiments.