Is it a roller coaster? A marble waterfall? Whatever you call it, it's a blast to build and just as much fun to operate. When we're at a show, we find we have to "test" our display model every time we walk by.
Turn the crank, and a bucket on the end of an elevator arm carries the marbles to the top of a ramp. From there, a series of ramps moved the marbles through a series of ramps, there to be lifted back up and do it all over again.
Finished model is 10" wide x 9" deep x 8" high. Kit comes with 227 laser-cut plywood pieces, steel marbles, bushings, axles, glue, and all other parts needed for assembly. Recommended for ages 14 & up.