SNARFEM

Snarfem, a two-player game of removing pebbles, originated in Mithicus and comes from an ancient Mithican word meaning "to collect pebbles or small stones." The purpose of snarfem is to remove the correct amount of pebbles during each turn that will force the opponent to take the last pebble. This game is a common source of entertainment along the streets of major cities.

SOURCE(S): Zork Zero, Zork: Grand Inquisitor (official strategy guide)