Figure 5.

A representative sample of 20 out of the 162 stimuli used in this study. Pictograms of the stimuli are arranged in increasing order of average ray strength reported by our sample of observers. Top rows: weak ray strengths. These rows are predominantly made up of triangular polygons, low-contrast stimuli, and nonbisecting stimuli. Second to last row: stimuli with moderate experienced ray strength—predominantly bisecting pentagons. Bottom row: These five stimuli evoked the strongest ray experiences. These stimuli consist of high-contrast bisecting heptagons with several wreaths. This stimulus is made up of several interlocking polygons that bisect each other’s faces (see the Method section for details). Most observers perceive fleeting rays, beams, or lines emanating from the center that appear to be brighter than the background. The label above each icon indicates the level of the independent variable, in order (number of vertices per polygon, contrast, line width, number of wreaths, and whether the polygon faces bisect each other). The RS value below each icon denotes the average experienced ray strength.