vimeo.com/41600016
Four separate drawing machines constructed out of mostly wood. They are a ball in ink rolling around a pivoting platform, a series of markers rotating above a spinning piece of paper, magnets rotating on gears underneath paper moving graphite and finally a swing type construction with dripping paint on it.

What I enjoy about these is the purely physical nature of the mechanics which generate the output. Each one has a core, distinct physical property it uses as its theme and main mechanic. I think they are great starts and a lot can be done to expand and develop the mechanics. Currently each one seems to produce nearly identical output each time it is used. Adding some variance or having the users input directly influence the work would make the piece and product more interesting.