Hall of Four Spheres

Designing a Tumbling Dungeon is proving more difficult than I'd hoped. At least, in balancing how interesting the turned chambers are with the complexity of explaining them. I thought I might put up some chambers piecemeal as they come to me.

The Hall of Four Spheres is first encountered as a hallway with domes in the flour. These domes are made of stone/iron/brass and have inscriptions of astrological signs on them representing four skies:

The domes are actually full spheres resting in hemispherical depressions in the floor.  When the hallway is rotated (or the gravity is switched to either of the two walls or the ceiling), the spheres will roll, blocking the passage.  Children, hobbits, and talking dogs may be able to slip between the spheres and the walls of the passage when blocked, but then they'll have to fight the grue alone.  There could be interesting inscriptions in those depressions revealed when the spheres roll free, you might need a child, hobbit, or talking dog to squeeze in there and see.