Sometimes a man is at his most ingenious when he is cornered. A new photo series highlights this fact by showcasing a string of improvised tools crafted in some of the deepest and most depressing corners of all: prison cells.

Marc Steinmetz's photographs show the handiwork of inmates who went to great lengths to get an edge or merely survive while institutionalized. Many of the inventions are weapons, like the homemade shotgun above, others were more artistic in nature, such as a rudimentary tattoo gun. See the whole photo series here.