See also optical illusions and patterns/textures.
Photo(s) by Buro Destruct on Flickr.
Contributed by Florian Hardwig
Contributed by Edgar Walthert
Contributed by Milos Mitrovic
Contributed by Swiss Typefaces
Contributed by 205TF
Contributed by Sandoll Inc.
Contributed by Jorge Iván Moreno Majul
Contributed by George Triantafyllakos
Contributed by Type@Cooper
Contributed by Marçal Prats