  Gravity is now understood to become simple on-shell. We sketch how it becomes
simple also off-shell, when reformulated appropriately. Thus, we describe a
simple Lagrangian for gravitons that makes use of a certain complex of
differential operators. The Lagrangian is constructed analogously to that of
Maxwell's theory, just using a different complex. The complex, and therefore
also our description of gravitons, makes sense on any half-conformally flat
four-dimensional manifold.
