"Take Bally Technologies and WMS Gaming (formerly Williams). Though Bally has built slot machines since its start in the 1930s, both companies found their early fortune making pinball machines. In the late '70s, coin-op video arcades devoured the pinball market, and these scrappy multi-million-dollar corporations (along with a new startup, Konami) adapted to the new business. (Bally/Midway: Space Invaders, Tron; Williams: Joust, Robotron; Konami: Gyruss, Time Pilot, Super Cobra.) They all made big bucks until the arcades dwindled, and then, as before, they moved on - to the richest field yet."