[math-fun] beautiful equations and E.T.

Hello, they made a poll asking what are the most beautiful equations to a group of people. http://news.bbc.co.uk/1/hi/magazine/3721406.stm Euler's equation came second : exp(Pi * i) + 1 = 0. Maxwell equation came first. I think that these people are in physics. Nevertheless, I am wondering what if we would make a kind of message to extra-terrestrial intelligence and we would like to show them that we know all these things. What would be the best way to write them down in a universal language because for ET the equation exp(Pi*i)+1=0 means nothing at all if we can't explain what is Pi, e, 1, 0 and the equal sign, isn't? Any clue? ps : E = Mc^2 is only the 6'th. Simon Plouffe