TIL the original Zamboni machine was built on a Jeep, and was popularized by a touring ice skater who happened to witness it: Sonja Henie.
Here is the man himself. Frank Zamboni.
His machine scrapes the ice, augers it into the tank, washes it, storing the dirty rinse-water, and then melts it and spreads it evenly behind with a "towel", where it quickly re-freezes evenly.