The 13th card of a Tarot suit shows us a teacher, and in computing tarot, that teacher is a person who teaches you about the reflexive, universal nature of computing. For the suit of swords, that teacher is The Mathematician. Computers are a blunt imitation of mathematics. A lot of the development of Mathematics has been motivated by engineering and mechanism, but for digital computers, this is the reverse: the mathematics preceded the mechanism. Behind and beyond and before computers, motivating them, there is a truth. We learned about hypothetical computers as objects of pure mathematics, and then tried to build them in reality.