Spot a mysterious X mark near your home? It could be more than kids playing—some burglars use chalk symbols to mark targets.

Have you ever wondered how long of a line your bones could draw if you removed them and used them like pieces of chalk?

Chalk is fun to draw with, and some people even get really good at using it to make art on the sidewalk. If you don’t like tediously developing such skills, though, you could go another route.