By 1975, Richard Davis had been shot in the chest at close range 192 times.
But not only was he completely healthy, each of these bullets had been shot by Davis himself as part of a demonstration to sell his new product: the bulletproof vest.
Playing with firearms is always a bad idea, but after testing his design on empty vests, Davis became convinced that taking a bullet himself was the only way to prove the vest's efficacy.
And when people saw Davis walk away with just some stinging pain a minor cut, they may have stopped questioning his sanity and started wondering how such a light, flexible piece of clothing could stop a bullet.
The secret was in the material: a synthetic fiber invented a decade earlier by a material chemist named Stephanie Kwolek.
Her employers at DuPont had found huge success with nylon, the world's first synthetic fiber, and they wanted Kwolek to create something even stronger they could use to mass produce durable, lightweight tires.
Like all synthetic fibers, nylon is a polymer: a long chain of repeating molecules, or monomers.
While some polymers repeat the same monomer over and over, others chain multiple monomers in a steady pattern.
It's these two variables — which molecules are involved and how they bond to one another — that give each polymer its unique properties.
So, seeking to build on the strengths of nylon, Kwolek began a lengthy process of trial and error, combining various monomers in novel ways.
