1. Crystals Wallpaper
iOS / Android (Free; has paid options)
Create polygon shapes that look like the facets of pretty gems. It's kind of impossible to get bored with this one, as the more you tap, the more random your design gets.
2. Prune
iOS / Android ($3.99)
This game is so gorgeous I bought it twice so I could use it both on my iPod AND my phone. Grow curling bonsai trees that branch out as you prune them. It's minimalist but beautifully colored, and never fails to relax me.
3. Tengami
iOS / Android ($3.99)
It's a pop-up book that lets you do so much more than just turn the pages--it has beautifully illustrated scenes inspired by Japanese art.
4. har.mo.ny
iOS ($2.99 each or $6.99 for all three)
I don't know exactly how the developers of these apps found out the most soothing palettes imaginable, but I'm grateful regardless. It was well worth spending a few bucks for these: it's a treasure trove of color. And there's (optional) music in the background that just adds to the loveliness.
5. Loop
iOS / Android (Free)
Oddly interesting, this app has beautiful puzzles that rearrange themselves when you tap the loops (or pieces of them) to link them into one big geometric beauty.
6. Stack
iOS / Android (Free)
As the title suggests, this cute and colorful game is about...stacking. It quickly becomes time-consuming, though, as you try your hardest to make your tower of blocks the prettiest pyramid ever!
7. Blackbox
iOS / Android (Free)
This is definitely a must-have for people who love mind tricks, and even for those like me, who suck at them, but are still going to try anyways and end up throwing their phone at something. Seriously, though, Blackbox looks great and has genuinely innovative puzzles.
8. hocus.
iOS / Android ($0.99)
This puzzle game has a minimalist design and Escher-worthy optical illusions. It'll have you turning your head to follow the twists and turns.
9. Ultraflow
iOS / Android (Free)
Use your strategy and timing skills to bounce your way through complex layouts.
10. PolyFauna
iOS / Android (Free)
A darker, more abstract visual experience from...Radiohead?? However you feel about the band, this is an app with really unique designs, and a cool soundtrack as well.
11. Polyforge
iOS / Android (Free; $0.99 to disable all ads)
Build beautiful geometric shapes that rotate as you try to hit all of their sides. It gets fast-paced after a while, but in no way less beautiful as you go from simple triangles to spiky stars with dozens of sides.
12. INKS
iOS / Android
An arcade classic with a twist--glorious splashes of inky paint bloom wherever the pinball goes.
13. Monument Valley
iOS / Android ($3.99)
Beautiful building game with lots of color. Want to make amazing works of architecture, but lack a magical world in which to do so? Then this app is for you.
14. Orbitum
iOS / Android (Free)
Tap the orbits into the right direction. So relaxing it's kind of hypnotic.
15. Isometric
iOS / Android ($1.99)
This app gives you endless possibilities. Create multi-dimensional designs that look like museum material.