  Rotor walk is a deterministic analogue of random walk. We study its
recurrence and transience properties on Z^d for the initial configuration of
all rotors aligned. If n particles in turn perform rotor walks starting from
the origin, we show that the number that escape (i.e., never return to the
origin) is of order n in dimensions d>=3, and of order n/log(n) in dimension 2.
