Slinky is a failed Navy part that fell off a shelf.
In 1943 Richard James was designing springs to steady instruments on warships when one tumbled off a shelf and “walked.” His wife Betty named it Slinky. He later left the company to become a missionary in Bolivia. She ran it for decades, kept it modestly priced, and sold 300 million Slinkys.
Slinky on Brandseum