In 1482, DaVinci wrote to Duke Sforza to be a military engineer for his army in the fight against France. DaVinci got the job and worked in Milan for the next 17 years as a military engineer. During his first few years working in Milan, Leonardo designed many bridges and structures, including the self-supporting bridge. This bridge could be built in minutes and be built without fasteners or joints. It is a bridge made of beams that crisscross each other like scissors and use the pressure to hold each other stable; the greater the pressure the greater the stability. It was often used by the Milanese military at the time for its ease of use and it has been used in many parades and events as a short-term, safe bridge.

“Leonardo Da Vinci: Self-Supporting-Bridge.” Leonardo3, Leonardo Museum, www.leonardo3.net/en/l3-works/machines/1355-self-supporting-bridge.html.

Sniderman, Debbie. “Leonardo Da Vinci.” ASME, The American Society of Mechanical Engineers, 10 Apr. 2012, www.asme.org/topics-resources/content/leonardo-da-vinci.

Noe, Rain. “Leonardo Da Vinci's Ingenious Design for a Self-Supporting Bridge.” Core77, 6 Apr. 2017, www.core77.com/posts/65043/Leonardo-da-Vincis-Ingenious-Design-for-a-Sel....