Here, you will be looking at four sets of images that each flash for a second before the next image appears. As these four block images flash in order one a half-step in front of one another, our brains assume the darker colors (red and black) together and the lighter colors (green and white) together. This assumption (again, caused by our ability to distinguish the color but not the luminance of the image) gives these four stationary images the illusion that they are in perpetual motion, moving forward.

How It Works

Fools teach us not to make assumptions because doing so puts us at risk of being wrong. (Ever hear the corporate saying, “Assume makes an ass out of u and me?”) Yet did these fools know that being wrong can be fun. Take for instance our visual system: When it makes wrong assumptions it makes an ass of nobody, it makes us high—giving us a multihued visual diaspora coupled with a disjointed, disoriented feeling. We like that. You will too.

Equiluminance is a display in which the color components are organized in such a way as to trick our eyes (and brains). What happens is the colors in the image are so close in luminance—brightness—that they are recognized by our color-sensitive perceptions but not our luminance-sensitive perceptions. This discretion makes a stationary object appear as though it were moving.

The image here flashes black-and-white squares for one second; the second image flashes green-and-red squares, positioned a half-block off of the black-and-white squares. The third image is, again, black-and-white squares placed a half-block from the previous green-and-red squares. The final image is of green-and-red squares, a half-square off the previous block. (You get where we’re going with all this.) All this flashing and half-step moving creates a perception of motion.

Old billboards used equiluminance to make objects appear animated, even though they were just flashing sets of stationary lights.

Click the applet on this cool page to view an interactive example of Equiluminance.