I’ve always been a fan of squigglevision, 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.

I was immediately drawn to Squigglish because it’s a refreshingly simple drawing app with one purpose: to add lines that wiggle. You can choose to upload or take your own photo to draw on, or you can start from a blank canvas and create your own masterpiece. When you’re done, you can export it as a GIF or movie.

Squigglish was born out of code adapted from a previous hackathon in which Walch and PhD student Matt Jacobs tried to use math to correct essential tremor. “Essential tremor is a condition where one of the symptoms is wobbly handwriting,” Walch told The Verge over email. “Once we got that code running, we realized we could go the other direction, and adapt our code to introduce tremor into line drawings.”

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. Here’s an example:

“For Squigglish, I’m messing with the higher frequencies in the signal, to increase their overall strength by some random amount,” Walch said. “This adds the wiggle you see in the lines!”

Walch plans to add more to the current roster of five brushes and UI updates, as well as an eyedropper tool. “I’d love to make more mathematical animation tools, where artists and creators can explore the spaces created by parameters,” she said. “Math gives us some wonderful visual playgrounds. I think it’d be great to incorporate more interactive stuff like this into math ed.”

Squigglish! is available for free on the App Store, and an Android version is coming soon.