  Every isometry of a finite dimensional euclidean space is a product of
reflections and the minimum length of a reflection factorization defines a
metric on its full isometry group. In this article we identify the structure of
intervals in this metric space by constructing, for each isometry, an explicit
combinatorial model encoding all of its minimal length reflection
factorizations. The model is largely independent of the isometry chosen in that
it only depends on whether or not some point is fixed and the dimension of the
space of directions that points are moved.
