Robotime-rokr marble run race is based on great human engineering. They combine the beauty of science and machines, involving so many small gadgets. Build the set and crank the handle, watch marbles run crazy down the slopes and twisting turns.robotime-rokr marble run race is based on great human engineering. They combine the beauty of science and machines, involving so many small gadgets. Build the set and crank the handle, watch marbles run crazy down the slopes and twisting turns.many gear gadgets: consists of a tower distributor, spiral slopes, a crane lifer, a wheel lifter, a short slide and small switches. Intricate system of cogs, gears and wheels,full of crazy twists and turns.stem concepts: learn principles of science,technology, engineering and mathematics(stem)hobby & gift: precise laser cutting ensure you a fluent building experience. Also a great gift for family and friends.