I have overlaid two versions of the same image so you can see the various blending modes
Poly is an iPad photo-editing app that comes on more like a game than a serious productivity tool. And lest you think that you’re wasting your time on mindless frivolities, Poly is based on good, hard math.
The math used is called Delauney Triangulation, invented by Boris Delaunay in 1934. If you want to study it, you can check the Wikipedia page. If you just want to make cool, pointy pictures like the one above, you can just grab the $1 app and start playing.
These images, from the Poly iTunes page, show what you can achieve if you know what you're doing. Unlike me
Select a photo from your camera roll or just take one with the camera. You can then start tapping. This adds points to the image and starts the triangulation process. Whatever clever stuff is going on behind the scenes lays triangles over the image based on the colors behind them. You can set the blending amount to show no triangles, only triangles or a mixture of both.
The controls are very simple, with just add, erase and undo, as well as a few viewing options, and images are saved to your camera roll to be shared by other apps.
It’s a lot of fun. Now I’m going to go find a neighbor with a Christmas tree, snap a picture and make a blocky, triangulated version to use as a Christmas card. It’ll be just the same as the crap my two-year old nephew “sends” to me, only done with cool tech instead of stupid crayons (he can’t even stay inside the lines).