Ambiguous images which serve in the psychology of perception to demonstrate the way the mind habitually tries to achieve a coherent Gestalt. These are often seen as optical illusions. An example is a drawing of a cube made with twelve lines ? allowing for two interpretations of which edges are nearest and farthest. This alternating figure is commonly called a "magic cube": the transparent cube in the see thumbnail belowcenter below. Which of its sides is nearest to you? Is it the one made solidly green on the cube to the left or is it the green side on the cube to the right, or is there no nearest side at all?