CUBUS X Matrix Clear (BLUE Tint) Plastic 3D Ultimate Labyrinth with Steel Ball (XMatrix) Tricky, Very Tricky, 3D labyrinth with clear walls and steel ball. BLUE tint version. Objective: Navigate the steel ball from the center "X" on the gold side to the center "X" on the silver side. Compact Cube Measure 2.75 x 2.75 x 2.75 inches. Fully sealed. No way for steel marble to escape the puzzle. Very challenging due to the clear maze walls. Difficult to know where you are going and where you have been.