Mathematics
When my friend Harry was ordained a deacon, I wanted to create something special for him. In his day job he is a computer guy, and loves math and science. So I created a deacon stole with a stripe of spectrum colors wrapping from hem to hem. But the length of each piece of rainbow-colored cotton was dictated by the digits in pi, with the point in 3.14 etc represented by a triangle in honor of Trinity Episcopal Church, our home parish.