Amazing.

This is Clockwork, my fifth major K’nex ball machine, and my largest and most complex K’nex structure to date. It took 8 months to build, has over 40,000 pieces, over 450 feet of track, 21 different paths, 8 motors, 5 lifts, and a one-of-a-kind computer-controlled crane, as well as two computer-controlled illuminated K’nex balls.

[via Dave Banks]