So I had no idea where to put this question, but I figured that this was the safest place to post it without being scolded for wrong location. Anyways, the other day, while out in our boat, I closed my eyes quickly and had one of those after-image-things. You know when you're looking at something, and close your eyes and the you can see the after image of it in your closed eyelids? Well, I had that, but it wasn't any object nearby. It was a symbol that I've never seen.
It looked like this:

I tried to match it with any of my surroundings, to see if I was just getting a strange angle of an object nearby, but there was nothing in that shape at all and it didn't make sense. I've never seen anything like it, but I can make out quite obvious letters. The reason they're upside down is because that is exactly what I saw for about a full minutes, as it lingered before my eyes.
I see an R, T, C, and an O. Do you see anything else? Have you ever had anything like this happen to you? Although I've never seen this symbol before, is it possible to have an after-image such as this a long time after seeing a symbol? Feel free to ask questions if it does not make sense. It's quite hard to explain.
sweatdrop