Robotime-ROKR Marble Night City is based on great human engineering. This marble run product combines the beauty of science and machines, involving so many small gadgets. It is a self-assembly 3D wooden puzzle with Tower Distributors & track race balls. Build the set and crank the handle. Watch marbles run crazy down the slopes and twisting turns. Breakthrough material restrictions and incorporate high-transparent acrylic. With a funnel-shaped track, the total length is extended to 2.5 meters. Rotate the handle, the steel ball will reciprocate along the track to experience the creativity of precision machinery with this wooden marble run puzzle.