Gestalt

This image includes several of the Gestalt principles. The black line segments in the middle of the image are all similar making them look like they belong together. The same line segments are all close in proximity, further enforcing their relationship. Because of closure, the two apparent groups of segments in the center appear to be two tall rectangles. These rectangles are both close in proximity to each other and similar, making them appear to belong together. Closure again is present as the mind completes the oval that seems to surround the rectangles. The groups of horizontal lines at each corner appear to continue through the oval to the corresponding group of horizontal lines. There is also some figure/ground eye-trickery going on here, as the eye attempts to determine if the white oval is the figure to the horizontal line ground, or the ground to the vertical rectangle figures.