  It is known that some good linear codes over a finite ring (R-linear codes)
arise from interesting point constellations in certain projective geometries.
For example, the expurgated Nordstrom-Robinson code, a nonlinear binary
[14,6,6]-code which has higher minimum distance than any linear binary
[14,6]-code, can be constructed from a maximal 2-arc in the projective
Hjelmslev plane over Z_4.
