I'd like to tell you about a program I have on Google Play Market. https://play.google....s.SourcesGL.pro
SourcesPro is, I think, genuinely unique. It is a kind of generative graphics app, which lets you combine simple repeating "sources" and see what happens. The app also animates these images, so you can watch the interactions change. On a decent modern device, high quality output images up to 2000 pixels per side can be created - enough for printing, wallpapers, etc.
There is also a free version with some limitations - no fancy functions, small output only, 2 min pause after 20 mins of use. https://play.google.....SourcesGL.lite
This is a deep program with countless permutations. Maybe not for the casual user, it is probably more for the creative type who likes messing about with photoshop or fractals.
I hope you find this app of interest. Sources is essentially very simple to use, but the best results come with some experience. It produces images that no other graphics program on any platform, that I'm aware of, could manage without huge effort.