  The low velocity dynamic of a doubly periodic monopole, also called a
monopole wall or monowall for short, is described by geodesic motion on its
moduli space. This moduli space is hyperkaehler and non-compact. We establish a
relation between the Kaehler potential of this moduli space and the volume of a
region in Euclidean three-space cut out by a plane arrangement associated with
each monowall.
