This is such a great tool, try configuring it for roundabouts and have a great deal of learning by modeling.
This is an online edition of the classic technical reference Five Hundred and Seven Mechanical Movements by Henry T. Brown.
This site contains the original illustrations and text from the 21st edition of the book, published in 1908. It also includes animated versions of the illustrations, and occasional notes by the webmaster.
I am having fun with this today!
Engineering ToolBox – Resources, Tools and Basic Information for Engineering and Design of Technical Applications!