Simulation and animation of spring mass damper System on Visio.
https://youtu.be/UQmB9m-F8rQ (https://youtu.be/UQmB9m-F8rQ)
.vsd file is also attached for older versions of Visio but I tried it only on Visio 2013.
For the necessary files and references to make it work http://visguy.com/vgforum/index.php?topic=7981.msg35637#msg35637 (http://visguy.com/vgforum/index.php?topic=7981.msg35637#msg35637)
That is pretty amazing.