Figure 1: The nine-circle version of the Rotating Snakes Illusion (RSI) (a) used in the test phase and its static control stimulus (b).

From: Do Fish Perceive Illusory Motion?

Figure 1: The nine-circle version of the Rotating Snakes Illusion (RSI) (a) used in the test phase and its static control stimulus (b).
Figure 1

Those stimuli were created by the authors of this article based on the original pattern by Kitaoka and Ashida13.