 # outside or on the circle through points a, b and c. A positive return value
 # means inside, zero means on and a negative value means outside.
 inclusionInCircumCircle = (a, b, c, d) ->
-
-  # Equivalently, we can ask whether the lift of d is below, on or above the
-  # plane formed by the lifts of the points a, b and c, which we can readily
-  # read of the dot product of the lifted normal and the vector from the lift
-  # of a to the lift of d.
   liftedNormal(a, b, c).dot lift(d).minus lift(a)
 
 

    # The method `plus` creates a new Delaunay triangulation with the given
    # `Point2d` instance added as a site.
    plus: (p) ->
      # We return the current instance unchanged if the site is already in.
      if @sites__.contains p
        this
      # Otherwise, there's work to do...
      else
        # ...


    # triangle in this triangulation, if any, which contains the two or three
    # given vertices in the correct order.
    find: (a, b, c) ->
     if c?
        seq(seq(a, b, c), seq(b, c, a), seq(c, a, b)).
          find((t) => @triangles__.contains(t))
