thest-site
Delaunay triangulation of nearly cocircular points may produce a poor
approximation:
<pre>
         rbox s 5000 W1e-13 D2 t1002151341 | qhull d Qt
         rbox 1000 s W1e-13 t1002231672 | qhull d Tv
</pre>

<p>During
construction of the hull, a point may be above two
facets with opposite orientations that span the input
set.  Even though the point may be nearly coplanar with both
facets, and can be distant from the precise convex
hull of the input sites.  Additional facets leave the point distan