Roger W. Sutton, an inmate at Mountain View Correctional Institution in Spruce Pine, NC, built a working clock out of paper, popsicle sticks, and pencils, using only a razor blade, tweezers, and nail clippers as his tools (Mountain View must allow access to sharp objects). The clock has beautiful colors, too! I’d imagine that being imprisoned gives people a keen interest in the passage of time– and that there are probably many other amazing but little-known projects by prisoners. Link.
