Which plate needs to be cleansed when Tolandball moves to the ceiling of the room during the Prophecy dungeon 2nd encounter?

Cleansing any plates will work, but if you want extra efficiency, here's what to do. First of all, here's some insight about this encounter. The goal is to draw a circle on each side of the cube above you, 6 in total. Toland always just shows you a random side that doesn't have a circle on it.

When Toland is on top, look at the cube and find a side that doesn't have a circle on it. (In this case it's the one on the right.) Once you do, cleanse that side. If all the sides around the cube are already marked with a circle, just do any one you'd like, as the goal is to rotate the cube and to get to Toland's side.