Klein disc, Poincare disc, Half-plane, Beltrami pseudosphere.
All angles of parallelism are less than a right angle.
Two lines with a common perpendicular are ultraparallel. An ordinary point is a point in the model. An omega point is not . If two hyperbolic lines are sensed parallels, we say that they meet at an omega point. In the Klein or Poincare disc models, the omega points are on the circumference of the circle.