In the opening scene, the first thing we see is  the Pi symbol, this isn't shown in the middle of the screen it almost seems out of place which can make the audience feel exactly the same, and very uneasy, although white symbols/writing on a black screen can connotate that whatever is in white is a good thing, i believe that it makes it stand out more and have a more  powerful effect on the viewers. Following this the actual number that makes up PI begins to be almost typed out, this will make the audience feel very much on edge as they want to know who it is that's typing it out or why they are seeing the whole number.