Hollow Glass Cubes

Hollow Glass Cubes are an obstacle introduced in Checkpoint 9. They are just a cube frame, and may hold objects inside them (another cube or an Octahedral Crystal), or just be empty in Training Mode (where the inner cube is removed) or the Disappearing Crystal Glitch (where the Octahedral Crystal is removed.). They also appear in Zen Mode and the Local Multiplayer. They rotate on a cube-shaped metal piece. Sometimes the cubes may spin out of sync.