of the way to the boundary of the cone, and in the direction of
a 30-60-90 triangle. If one follows those coordinates, they hit
at ``(1, sqrt(3)/2, 1/2)`` having unit norm. Thus the
- "horizontal" distance to the boundary of the cone is ``(1 -
+ "horizontal" distance to the boundary of the cone is ``1 -
norm(x)``, which simplifies to ``1/2``. And rather than involve
a square root, we divide by two for a final safe radius of
``1/4``.