Simultaneous Figure Ground is having your eye trying to figure out which part of the composition is in the foreground and what is in the background. Or do they merge together to make a illusion middle-ground? That's the beauty of this principle by Gestalt. In the two examples below, you can't really tell whether the black or the white squares are in the front or the back. It plays tricks on the eye because neither the black or white is suddenly cut of in the design. The black flows and is uninterrupted by the white squares and vise versa. In the grey value piece, it adds the effect of of the squares "breaking off" and fading into the the other's contrasted value.
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