According to Hawking and Ellis, another remarkable feature of this spacetime is the fact that, if we suppress the inessential y coordinate, light emitted from an event on the world line of a given dust particle spirals outwards, forms a circular cusp, then spirals inward and reconverges at a subsequent event on the world line of the original dust particle. This means that observers looking orthogonally to the e2 direction can see only finitely far out, and also see themselves at an earlier time.