This image was taken at an abandoned gold mine/ghost town in Nevada. It was used to crush rocks taken from the mine for processing with cyanide to extract the gold. What I liked was the various shapes (circle, curved, straight, angled, triangular) and the different textures.

Olympus OMD-EM1 with Olympus 12-40mm lens @32mm, ISO-200, f/8,1/60 seconds. Post processed with GIMP