Figure 10. Effect of background on RAP motion. Gradients are black-to-white (a-c), black-to-gray (d-f), and gray-to-white (g-i). Backgrounds are black, gray, and white. Best viewing is obtained with a single magnified panel in peripheral vision (for example: magnify the pattern on your computer display to 15 cm in diameter, view from 50 cm, and fixate 15 cm from center of pattern). The reader can expect to see different speeds and even directions in the different patterns, and different observers report different motions for a given pattern under similar viewing conditions. Most of these patterns rotate counterclockwise, but the authors see (g) to rotate clockwise. For some observers, careful viewing of (a) may reveal a fast clockwise initial rotation followed by slow counterclockwise rotation, for each new fixation.