Spritz is a quite remarkable piece of software, that tries to eliminate the need to move your eyes while reading. To do this, they try to calculate where the eye would want to focus, and then putting that spot at the point where it is already looking. A while back i tried building my own version of Spritz, just to see how far i could go without spending a couple of years researching reading. Try it yourself, and make sure to compare it with the original.
Original version: SpritzInc.com
My version: Codepen