Most inventors hope to leave an indelible mark, some figuratively but a few, like Edson P. Clark do so literally. Edson received U.S. Patent No. 56,180 on July 10, 1866:

This was actually an improvement to the indelible pencil in U.S. Patent No. 24,195 from May 31, 1859:

Edson’s pencil was a commercial success, and examples survive today.