Enlighting Mind Pannello 2

Bulging Shapes

Although this image is perfectly flat, many observers perceive four convex hemispheres emerging from the checkerboard background. The illusion begins with the gradual transformation of the central square into increasingly elongated rectangles along the horizontal and vertical directions. This geometric distortion creates a powerful perspective cue that makes each quadrant resemble the surface of a bulging hemisphere.

In the upper-right and lower-left hemispheres, the illusion is further strengthened by the addition of small black and white dots inside the checkerboard pattern. These dots introduce subtle variations in local contrast and texture that enhance the perception of curvature, making the hemispheres appear even more rounded and protruding. Together, the distorted checkerboard and the dot pattern provide the brain with visual cues normally associated with real three-dimensional surfaces.

This artwork was created by Gianni A. Sarcone, an Italian visual artist, author, and researcher whose creations explore the fascinating relationship between geometry, perception, and cognitive science. His optical illusions demonstrate how our visual system infers three-dimensional shape from two-dimensional patterns. One of the pioneers of these artistic and perceptual principles was Victor Vasarely (1906–1997), the father of Op Art, whose geometric compositions transformed flat surfaces into vivid illusions of depth and volume.

Perception Insight

Your eyes receive only a flat pattern of black and white shapes. The sensation of four protruding hemispheres is generated entirely by your visual system, revealing how the brain infers three-dimensional form from perspective, texture, contrast, and spatial organization.