I was trying to explain special relativity to a few friends in a simple way and wound up with an analogy using a c unit circle.
I was using y as travelling in time, x moving in space; move in space and you are borrowing from your clock-speed. E.g. the twin paradox: Your travelling twin has borrowed clock-speed. Twins clock was slower -> twin is younger.
What is the problem with representing relativity using a (c) unit circle from an observers point of view? Anything Lorentz or Minkowski would be out of the question of course, I'm looking for a layman friendly description that is close to true.
The circle discussed, was in my mind a half circle $y>=0$. Where $y=0$ would be a photon.