Squigglish is a new app in town which uses squiggle vision, the animation effect in which lines oscillate to make static scenes feel more dynamic. It involves animators drawing the same image multiple times and looping the drawings in a sequence to create depth and movement.
Mathematician and comic artist Olivia Walch is a fan as well, and her latest app Squigglish makes this effect easily achievable for even the most casual doodler.
The app makes use of the Fourier series, which decomposes signals into basic building blocks with different frequencies. The team used the Fourier series in another project called SketchAnything, which takes images and breaks the lines down to their different frequency components. It starts with the lowest frequency, which creates the simplest version of the lines, and gradually adds the higher frequency details until it creates something closer to the original drawing.
Squigglish! is currently available for free on the App Store, and an Android version is coming soon.
Source: The Verge