There is no doubt that I, also, had long been aware of the problem, i.e. producing X-ray interferences, before the inherent difficulties had finally been surmounted.
If you're old enough to have a job and to have a life, you use Facebook exactly as advertised, you look up old friends.
Pilates is my favorite meditative way to get in shape. I don't like the gym and I don't like running, so I just lay on my Pilates reformer. It's great.