In 1925, 20 years after completing his work on the airplane, Orville Wright patented a spring-propelled doll:

This invention relates to toys and more particularly to that type of toy in which any object, such as a doll, is projected through the air and caused to engage and to be supported by a swinging bar or other suitable supporting structure.

I don’t know the story behind it. Orville was 53 years old. Neither he nor Wilbur had any children, and their sister didn’t marry until the following year.

Perhaps he was tinkering just to tinker. “Isn’t it astonishing,” he once said, “that all these secrets have been preserved for so many years just so we could discover them!”