Theo Jansen builds amazing walking machines.
Each leg is an eight-bar linkage. The Wolfram Demonstration Project models this linkage in a Mathematica notebook. See the link:
http://demonstrations.wolfram.com/ATheoJansenWalkingLinkage/
[vimeo]http://vimeo.com/1242383[/vimeo]
Periodic Table
The National Institute of Standards and Technology provides an on-line periodic table. Access it and other information at the link: Periodic Table
National Institute of Standards and Technology
This is a link to notes on Geometric Design and Tolerancing by Prof. Graeme Britton of Raffles Design Institute, Singapore.
Prof. Britton\’s Notes on GD&T
A pdf version of Prof. Britton’s lecture is available at:
http://synthetica.eng.uci.edu/mechanicaldesign101/GDandT.pdf
Here is another excellent set of notes from the Technical College of New Jersey on geometric dimensioning and tolerancing.