The Ninefold Square
“This translation plane is defined by
a spreadset in a 2-dimensional
vector space over the field GF(3),
consisting of the following matrices.”
Priv.-Doz. Dr. H. Klein,
Arbeitsgruppe Geometrie,
Mathematical Seminar of
Christian-Albrechts University
(See Log24, The Nine
and Translation Plane
for Rosh Hashanah.)