Caution: Sharp Edges

This one's for my photo class students, who watched me do this live and in person. Thanks for the idea (I think it was Charlie's or Karen's).

Camera: Canon EOS 50D Lens: Canon EF 28-80mm f3.5-5.6 Light: Speedlite 550EX ISO: 400 Exposure: f0 @ 1/160 sec.