er improvements are needed, primarily for 4-D and higher.
For example, the Delaunay triangulation of 400 pairs of nearly adjacent 5-D points frequently fails with
a topological error (<tt>eg/qtest.sh 10 '400 C1,2e-13 D5' 'Q14 d Qbb'</tt>).

<p>For Delaunay triangulations, the problem typically occurs for extreme points of the input
set (i.e., on the edge between the upper and lower convex hull).  After multiple facet merges, four
facets may share a "dupridge" and must be merged.
Some of these facets may be 