I change my wallpapers all the time. On my phone, my iPad, my laptop — it's a thing I stare at for hours every single day, so I like to switch it up. But finding just the right image can be hard. It needs to be interesting and colorful, but not so much that it makes my screen look cluttered. I cycle between various bits of abstract art and concepts for weird new spaceships, but it usually doesn't feel quite right.

Crystals for iOS is the perfect solution to my problem. It's an app that lets you make slick and colorful images made of polygons, simply with a touch of your finger. Tapping the screen will create the tip of a polygonal crystal, splitting the screen into triangles, and with multiple taps you can create complex crystalline images. Each tap is emphasized with a satisfying ding, and there are a bunch of different color options that can dramatically change how things look. The most impressive thing is that it's pretty hard to make something that doesn't look amazing: Crystals is more of a visual toy than a proper art tool, and it's a lot of fun to play with. Once you complete an image there isn't much you can do other than save it or export it as a PDF or SVG file for tinkering in another program.

Crystals is free to download on iOS, with $3 worth of in-app purchases to add new color options (you also get a few bonuses if you already own Isometric). It's far from the most robust art tool, but that's really not the point: it's just a great way to zone out while making pretty pictures. "I hope people have fun and can relax while using these apps," Peters says of his work, which may soon include a third app involving dots. And as an added bonus, I have a huge stack of wallpapers that should keep my iPad happy for the foreseeable future.