This topic is about the symbols on driver helmets and about their meaning. I mean things like this:
The two cards on the back of Alonso's helmet refer to his two titles - and also on his passion for playing cards:

There are more tricky and less obvious ones though. For example, Michael Schumacher had some Chinese signs on his helmet. Those were the names of his family members. Here it's Mick - his son - (above the AMD sign) and Michael, on the other side it's Gina Maria and Corinna (his daughter and his wife).

This is Gina's name:

Michael has 7 stars on the top of his helmet, but those are NOT to represent his titles. They were there since his Benetton times (although the number of the stars varied at the beginning, there was five and I think even four, but he was still at Benetton when it became 7). IIRC he once commented he just likes the starry night sky, so that's why it's on his helmet.
As we know the Hill's family helmet was pretty special with the white stripes representing blades for the London Rowing Club. Damon Hill had this to say about it:
"Basicly I sport the same helmet colours as my father. It's very dark blue with white rowing bladed signifying the rowing club of Putney, London. Both my father and my mother were very succesful rowing athletes. They even met at the rowing club! I went for the same design for two reasons. First, I am proud of it, and second, you can spot this design from far away. I'm not into rowing, but the club are happy that I keep up the tradition"

I'm sure there are a lot more designs (present or past) which have more to them than the driver just liking those colors and shapes, which have some sort of symbolism. Which are they?