If blessed, the scroll of magic mapping reveals the vibrating square.

There is a small temple-like structure around the Vibrating Square (not an actual temple) which gets destroyed during the invocation.

Make the Vibrating Square a brighter color than purple.

Treat the vibrating square (if you have located it) as a dungeon feature in the overview, so that the level is shown as having a vibrating square on it.

Make the Vibrating Square level into, rather than just another maze level, a level with 3 symmetric 7x5 chambers embedded in the maze, each with four exits, and a smaller 3x3 chamber at the bottom containing the upstairs. In the center of one of the 7x5 rooms is the Vibrating Square. This is intended to be a dark mirror of the Astral Plane.

The vibrating square level is just one big open rectangle with the vibrating square in its usual spots.

YAFMs (both regular and hallucinating) for sitting on the Vibrating Square. Something to do with a vibrating chair massage.

Allow teleportation onto the vibrating square, since it isn’t really a trap.