Update, 10/7: More background from Brian in Comments.

A guy named Brian Peiris figured out how to write code for graphics in virtual reality while in virtual reality itself, so he sees the changes as he implements them, and it's mind-bogglingly cool -- watch:

Specifically, as he explains, "I built a live-coding web app for the Oculus Rift where you code in JavaScript using Three.js and watch the world change around you in real-time."

"Very cool," said Philip Rosedale, when I showed him this video. "I want to hire the kid!" Rosedale of course, founded Second Life and is now creating High Fidelity, a new fully VR-integrated virtual world. As it happens, he and his team are already developing a comparable feature for High Fidelity:

"We are doing very similar stuff already with live Javascript code editing in Hifi," he tells me. "[T]he existing editor is live, and we are already displaying parts of the UI in the Oculus. So we'll definitely try this sort of approach."

However, he adds, there's one challenge they need to solve: