When you want a marble machine for no particular reason, your best bet is to visit Jazzmyn's post to Instructables.com. Therein she outlines all of the steps necessary for creating your own whizzing, whirring marble track, complete with links to the files and instructions for assembly. The precocious 14 year old is no newbie to the scene, so make sure you check out her other contributions and her website engineeringwithjazz.com - we're sure to see a lot more of her in the future! Read and see more at http://3dprint.com/75607/3d-printed-marble-machine-3/