I see marble runs evhrrweeye these days. I can think of at least 3 artists, 7 toy companies, and 10 museums with marble runs. However there's one thing about the marble machine in the tinkering studio that I think is unique, and that is that it never stays the same. The materials used and the objectives in mind are constantly in a state of flux. Reading the tinkering studio blog makes this obvious. I think this element of constant change is a really important part of tinkering. Just when you think you've run out of ideas, jump out of the box and try something different. Make a marble machine that makes music, or construct one out of nothing but toothpicks.