### Bianchi Orbifolds

Shown below are pictures of the 3-dimensional orbifolds which
are the quotient of hyperbolic 3-space by the Bianchi group PGL(2,O)
where O is the ring of integers in the imaginary quadratic field
of discriminant D=-3, -4, -7, -8, -11, -15, -19, -20, -23, -24,
-31, -35, -39, -47, -51, -56, -59, -68, -71. In each of these
cases the orbifold is topologically the 3-sphere with punctures
(shown as tiny circles), and the pictures show the singular locus
of the orbifold structure.

For more details see "Bianchi Orbifolds of Small Discriminant," a
brief unpublished report I wrote in 1983, available electronically as a
pdf file (95K, 6 pages).