Arthur Ehrat, a farmer who barely followed basketball, built the rim that bends on every dunk. In 1976, his nephew, a college coach, said players kept bending rims. Ehrat tried magnets in his shed. They failed. A coil spring off a John Deere field cultivator held instead. A player shattered two backboards in 1979, but the NBA didn't adopt the rim until 1981. Every dunk since traces back to a farmer's tractor spring.
