The Frog's Stepping Stones

The player begins on the stepping stone inside of the door. Printed on this stone are two cryptic numbers. The object of the game is to add up the two numbers and jump to the stepping stone which has, for its first number, this answer. You would then add up the two numbers to locate the next stone, and so on. The crystal is located inside the mouth of a frog at the opposite end of the room. Players were permitted to step on two incorrect stones before being locked in.