Beard Blindness

I saw a man today that had a strange manner about him. After watching him, I figured out that he must be a twin. I could tell by the way he tried to avoid certain expressions. Twins hate it when they catch themselves making faces that their twin is known to make. I wonder if a twin with Prosopagnosia would have a difficult time recognizing his own twin. A penguin with face blindness would also have it rough. At least humans with the condition can use hats or clothes or other distinguishing features. A penguin would have to walk around for hours looking for someone. "Larry? Is that you? No? Sorry. Larry? Is that you? No? Sorry. Larry?..." and so on for hours. I think I might be partially face blind. I can't tell people with beards apart. I also won't recognize someone even if I've known them a long time if they suddenly grow a beard or if they had a beard when I met them and they suddenly shave it off. If you're going to grow a beard, you need to commit to it.