CC-BY-SA-3.0
Taken from cmss13 at https://github.com/cmss13-devs/cmss13/blob/09a5191fb11aab8ddffe3f9be94292b53e4d96f6/icons/turf/walls/prison.dmi; CMU 3D original-corner crops and isolated composition. See SOURCES_PRISON_HULL.md.
