On io9, I saw this video of a 3D sculpture that can be rotated to form different shadows.
The artist is J. V. Muntean & this particular shadow sculpture, Evolution 1, can be rotated three ways to show the development of man from an ape-like creature.
These ingenious constructions can be seen as a metaphor- for the idea that the changing forms we see in the world around us are only slices of higher-dimensional space.
Like Plato's "Allegory of the Cave", our senses can't directly perceive these higher forms. We only experience the "shadows" they project into our awareness in 3D space.