Some people claim it's impossible to define what art is, but those people clearly haven't seen Flickr user Legohaulic's elaborate Lego cube that contains a twisting, turning ball maze on the inside. It's almost like a real-life version of an Escher sketch, and it equally deserves time in an art gallery.
Inside the CUB3, as Tyler's called it, there are actually four separate runs that the metal ball bearings are able to snake their way through after being lifted to the top. It's not compatible with other Lego Great Ball Contraptions, though, it's a completely self-contained piece that doesn't work with those plastic soccer balls. But that doesn't make it any less wonderful to see in motion.