In the weird mansion after collecting the kaleidoscope, the girl tells you another riddle and you will go through another door into a room with a projector. Summon Astral and fly into the corner with the rocking horse. Position yourself above the horse, then use Astral's abilities to walk. If done correctly you should drop in to the corner and be pushed outside the building. Return to flying mode and fly around the outside of the room. You might see things that can help you solve the puzzle.