Why Are Triangles Stronger Than Squares?

One shape is clearly superior and thus commonly used in construction and engineering, but why? HOW TO BUILD EVERYTHING Wednesdays 10/9c on Science http://www.sciencechannel.com/tv-shows/how-to-build-everything/ Subscribe to Science Channel: http://bit.ly/SubscribeScience Facebook: https://www.facebook.com/ScienceChannel Twitter: https://twitter.com/ScienceChannel