Gravitation (M. C. Escher)

Gravitation (also known as Gravity) is a mixed media work by the Dutch artist M. C. Escher completed in June 1952. It was first printed as a black-and-white lithograph and then coloured by hand in watercolour.
It depicts a nonconvex regular polyhedron known as the small stellated dodecahedron. Each facet of the figure has a trapezoidal doorway. Out of these doorways protrude the heads and legs of twelve turtles without shells, who are using the object as a common shell. The turtles are in six coloured pairs (red, orange, yellow, magenta, green and indigo) with each turtle directly opposite its counterpart.