make your own palimpsest
Random letters randomly upper and lower case with a smattering of punctuation and a few words and a short phrase overwriting each other continually. If you hit any key to save a .png version of that moment in time. It should open in a new tab/window of your browser. You can then right click and Save Image As (or your OS's equivalent), assuming you have an HTML5 compliant browser that supports the canvas tag. If at first you don't succeed try this: first click on the animation to make it the "active" element of your screen, then hit any key.
Source code: makeyourownpalimpsest