Shirt Design

I was sitting in class this week when I randomly had a cool idea for a T-shirt. The first row is my Doppler effect T-shirt.
Bottom left is my Brandon Sanderson shirt, and the bottom right is a Mormon or Christian shirt based on 1 Peter 2:2.
I feel like there are other geeky ideas for shirts that I have thought of before but I can't think of them now.

Funny thing is. I rarely wear shirts with words on them or even well know symbols or designs. I don't like the idea of making it too obvious what kind of person I am, or the things I like just by what I wear.... Of course the styles I choose to wear say some things already, but still.