If Nerd on the planet Nutley starts out in his spaceship at 20 KPH, and his speed doubles every 3.2 seconds, how long will it be before he exceeds the speed of light? How long will it be before the Galactic Patrol picks up the pieces of his spaceship?
If Roger Rowdy wrecks his car every week, and each week he breaks twice as many bones as before, how long will it be before he breaks every bone in his body? How long will it be before they cut off his insurance? Where does he get a new car every week?
If Johnson drinks one beer the first hour (slow start), four beers the next hour, nine beers the next, etc., and stacks the cans in a pyramid, how soon will Johnson's pyramid be larger than King Tut's? When will it fall on him? Will he notice?