We consider the question which I-graphs I(n,j,k) admit unit-distance representation
in the Euclidean plane with an n-fold rotational symmetry.
The answer to this question helps us determine the (euclidean) dimension of many
generalized Petersen graphs G(n,k).
Prisms, G(n,1), can be represented in this way only using degenerate unit-distance
representations; however, since they are Cartesian products, it it easy to find a
non-degenerate unit-distance representation without rotational symmetry.
The only generalized Petersen graph that cannot be studied using one of the two ways
is the arc-transitive G(12,5).
Unfortunately, there are some generalized Petersen graphs that result in various
types of degeneracies.