We study periodic tilings of d-dimensional space by clusters of relate
d zonotopes. For such tilings, the fundamental region relative to a fu
lly-dimensional translation group is the finite union of zonotopes con
structed as Minkowski sums of subsets of a given set of generating vec
tors. For any rationally-realizable zonotope Z, the rational realizati
on itself determines a unique periodic tiling in which one of the cell
s is the zonotope Z. In an effort to find analogous tilings using nonr
ational zonotopes, we conjecture a characterization in terms of a new
family oriented matroid structures, for which we provide axioms.