I thought this old one from Form-1 was simple but really cool; a good demonstration of what additive fabrication can do that other techniques would find challenging: https://youtu.be/qBmGDczDoe8?t=2m40sLikewise, this one: https://www.youtube.com/watch?v=vzHpN0FxvqU http://ift.tt/2aE56vv