In a \emph{rotor walk} the exits from each vertex follow a prescribed
periodic sequence. On an infinite Eulerian graph embedded periodically in
, we show that any simple rotor walk, regardless of rotor mechanism or
initial rotor configuration, visits at least on the order of
distinct sites in
t steps. We prove a shape theorem for the rotor walk on the
comb graph with i.i.d.\
... [Show full abstract] uniform initial rotors, showing that the range is of
order and the asymptotic shape of the range is a diamond. Using a
connection to the mirror model and critical percolation, we show that rotor
walk with i.i.d.\ uniform initial rotors is recurrent on two different directed
graphs obtained by orienting the edges of the square grid, the Manhattan
lattice and the F-lattice. We end with a short discussion of the time it
takes for rotor walk to cover a finite Eulerian graph.