Humanvision has a roughly 180° field-of-view. Pi isamathematical constant equal to the circumference of any circle divided by its diameter. Its symbol, π, appears in many mathematical formulae. There is even a day, March 14th (3-14) called "Pi Day", founded at the Exploratorium in 1988. Since π=180°, it is really a symbol that represents half a circle. So we propose the use of the semicircle symbol "◖", instead of the symbol π. We also propose the full circle symbol ⊗ or ⊙ to denote 2π. Thus we write: ⊙=360°.