A photo that appears to show a nude woman but is actually a bit of an optical illusion is sweeping the Internet.
The photo below looks like a naked woman posing behind another woman. But take a close look -- what appears to be the woman's nude body is actually her friend's arm.
The British tabloid The Sun said the image appears in an email with the subject "The awkward moment," with the line, "When your friend's fat arm makes you look naked."
It's not known who the woman are, or when the photo was taken.