Fascinating. However, don't think you are seeing the complete creation of an essay from its spark to completion. The first sentence appears (to me at least) considered and calculated. I'm sure much more thought has gone into the essay than the animation would suggest.
I've worked as a writer, and am currently in the process of writing a novel (the first I actually think someone would pay a penny to read) so I was actually about to comment that it does look like the complete process.
I'm sure a video of me writing would appear very similar. It can take me a long while to think of that first sentence, sometimes even a few days, but once I've got it in my head it usually comes out onto the page near-completed. Frequently I hit the first key and don't stop until 200 words later. However, it's once you get past what's sitting in the buffer in your brain that things drastically slow down.
As a slight aside, not knowing your personal history or the grades you got in high school, it's quite rare to see someone with a clear and (what appears to be) a natural writing talent coming from a programming background. From what I've seen, programming has a propensity to decrease literacy skills. It's especially impressive that it wasn't your standard five-paragraph essay, some people manage to succeed at those and fail at anything a hint more complex.
