In 1971, Fred E. Stuart patented a “firearm mounted in a shoe heel.” He envisions military personnel and police using it when “regular weapons have been lost or become jammed.”

The shoes can fire regular bullets, frangible projectiles, or even tear gas, and can be fitted with multiple barrels that fire independently.

Combine this with a reversible sole and you have the makings of a perfect murder — a concealed weapon that confuses the crime scene.