I am paying for a week of hacking in Seattle with some days of not research back here in New York City. The one research highlight of the day was Gia Dvali (NYU) telling us at lunch about his work on black holes as information processing machines. Along the way, he described the thought experiment of constructing a black hole by concentrating enormous numbers of gravitons in a small volume. Apparently this thought experiment, as simple as it sounds, justifies the famous black-hole entropy result. I was surprised! Now I am wondering what it would take, physically, to make this experiment happen. Like could you do this with a real phased array of gravitational radiation sources?