Reading mode for emacs

Reading lots of text on a computer isn’t the most fun thing in the world. I still like paper (or e-ink screens!). But computers still have the advantage of flexibility. I’ve tried some “alternative” reading methods like dictator before but didn’t like them much. I think a less radical approach is better. So, I’ve been hacking up a basic reading mode in emacs which just highlights a sentence at a time. I’ve found it pleasantly useful, especially for technical documents. Here’s the screenshot (code still in flux):

Dead simple, but it keeps my mind focused.