Shoe soles leave distinctive marks on concrete parking garage beams.
A low-angle view of white cement beams on the ceiling of a parking garage. Dark gray prints of shoe soles are extending across the bottom half of the cement beams. There is a light in between the first and second beam near the bottom right corner of the image. The third beam is partially visible at the very bottom of the image. Each beam is stained by the soles of different shoes.