This article is from the Final-Fantasy and other Square Soft Games FAQ, by email@example.com (Nick Zitzmann) with numerous contributions by others.
Square left a secret puzzle game in Final Fantasy I. To unveil it, you
first need to obtain Bikke's ship. Once you have the ship, get on the
ship, and - while holding your position - press A and B together about
You'll now find yourself listening to the Final Fantasy heroic theme
song as you solve a Rubik's Cube-like puzzle. Try and re-arrange all of
the numbers on screen, and leave the empty space at the bottom right
You'll be awarded some bonus GP for playing this game.