Parametric OpenSCAD joint connectors. These can be used to create hinge connecting pieces that have anywhere from 0 degrees to 365 degrees of range of motion.I used a similar syntax to Tony Buser's Pin Connectors ( http://www.thingiverse.com/thing:10541 ). At the moment the file is only somewhat documented, but I'm uploading a project soon that highlights how these can be used.The parts I've printed with this system snap-fit tightly together with no additional work. There is usually enough friction to the connections that hinges can be positioned or, with light sanding, swing freely.The included module, "joint_examples_with_descriptions_in_comments()" will create a set of example objects for you to try out.