Beautiful GIF by Étienne Jacob and I love the way this looks in that tiny twitter-compression shown on tweetdeck on a lowrez-display on my old macbook air (GIF below), because this animation with these circular patterns triggers a moiré effect which is triggered by the algorithm that moves the circles and the position of the elements and the pixel smoothing (anti-alias) effect of the operating system. The fonts you read on a screen are smooth, because the pixels are not black and white, but in shades of grey and these shades have to be computed. Same for the pixels in this animation: The system decides with its anti-aliasing-algorithm, which shade of grey the scaled down pixelversion of the otherwise white dots in the animation become.
And by combining this grey-pixel-algorithm with the animation-algorithm, you create different frequencies of numbers and sometimes they fit (pattern), sometimes they don't (noise) and the patterns in that noise create the short animation you can see in the small GIF shortly before the end of the loop, but not in the big GIF. That, kids, is a moiré effect. It also happens when you overlay different frequencies of lines or dots and its also the reason why the CMYK-Print-Stuff looks the way it does because these angles generate the most noise and the illusion of a good image.
I love the moiré effect since forever and even more since I know what it actually is and this one is a nice example of a moiré-effect generated not by static patterns in print, but by complexity-reduced representations of moving algorithms.
— Étienne Jacob (@EtienneJcb) December 30, 2018