speaking of flickering lights
I once met an astronomer at Mt. Wilson who hated fluorescent lights. He claimed he could see them flickering. Apparently his persistence of vision was quite short. We are all made a little different. He made them put in incandescent lights along with the fluorescent in all the buildings so the flickering would not bother him. When he came into the room they would have to switch to the incandescent lights. He was quite an eccentric and interesting fellow.