Symetria

Hi, my name is Karolina. I come from Katowice where I used to live with my mom and my cat Pętelka, but now I live in Wrocław where I study maths.

As maths is my little passion I would be grateful if you could send me a stamp or postcard linked to it. It could depict a famous mathematician or maybe a famous theorem. I know that this is not very popular topic but I do have some hopes anyway.
I also like cards with written name of place, where you live (like Katowice, Berlin, London etc.). If you don't have this type of postcards that's not problem - every card is a very nice surprise.

If it's not problem, tell me some stereotypes that are common in your country (eg. about women, other nations) or superstitions (funerals, weddings, birthday, holidays, ...).

Dear people from Russia!
Could you write things mentioned above both in English and Russian. I'm studying Russian at the moment and it would be helpful to know your language even better.

Thanks for every postcard you sent!