See also perspective effects and Necker cube.
Contributed by Slope Agency
Contributed by Jonny Black
Contributed by David Jonathan Ross
Contributed by Ciarán
Contributed by Benjamin Jackson
Contributed by D Jones
Contributed by Jorge Iván Moreno Majul
Contributed by Betty und Betty
Contributed by Matthijs Sluiter
Contributed by Swiss Typefaces
Contributed by Arnaud Aubry
Contributed by Florian Hardwig
Contributed by Vegar Bakken