I saw this old sedan bulldozer at an antique engine and tractor show near Ft. Pierce, Florida and took a color photograph of the tread sprocket using an Olympus E-520 with an Olympus Zuiko Digital 14-40 mm lens,handheld with no flash at 1/160 sec, f8, ISO 100 and 31mm focal length. Then I used Nik Silver Efex Pro to convert it to this monochrome image.