Figure 2.

(a) An illustration of synesthesia elicited by local/global forms. (b) An illustration of a cyclopean numeral (a “2” in this example) created by random dot stereoscopy (readers with access to red-green glasses can confirm the presence of the digit). (c) An illustration of a numeral defined by motion. The arrows indicate the directions in which dots moved within regions of the animation defined as “figure” and as “background.” In the actual animations, all dots—those defining the figure and those defining the background—were black against a white background, the numeral being defined solely by differential motion of the dots. In this schematic, different color and shading are used for illustrative purposes only.