This article is from the Final-Fantasy and other Square Soft Games FAQ, by firstname.lastname@example.org (Nick Zitzmann) with numerous contributions by others.
The puzzles in this dungeon range from slightly confusing to maddening,
but they are all solvable. For hints, you need to read the writing on
the walls, which usually give adequate (but vague) hints on how to solve
Does writing on the wall scare you? If so, read on...
For the first puzzle, you need to move to various places in the room to
get three blocks to appear. The exact placements of the triggers are
hard to describe, but here's a hint: Once you've got one down, don't
push it in quite yet. One of the triggers may be on top of one of those
stones, and you'll need the block to reach it.
For the second puzzle, avoid walking in the middle of the room. Walk on
the sides until you reach the end of the room. Note the direction which
leads to the dead end of the room you're in. Walk in the opposite
direction, straight down the middle, until your characters fall through
a trap. At that point, press and hold in the same direction as the dead
end to find a secret passage.
For the third puzzle, remain calm when the ceiling caves in. If you
don't move an inch, it won't hurt you. Jump on top and ride it back up
to find the room which takes you to the next puzzle...
For the fourth puzzle, you're in a room with water levels ranging
between 1 and 10, and starts at level 10 (the highest). The object is to
set the water level to 5. There's a switch on one side of the room which
enables you to switch between filling three and seven levels at a time.
(It defaults to three.) So, here's the strategy: Press the button to
drain the water level _three_ times, to lower the water level to 1.
Press the switch on the wall with seven marks to make the water level
refill by seven spaces. Press the other button to fill the water, and
it'll reach level 8. Now, press the switch with three marks to go back
to filling three levels. Drain the water once, and it'll reach level 5.