  Using high-speed photography, we investigate two distinct regimes of the
impact dynamics of granular jets with non-circular cross-sections. In the
steady-state regime, we observe the formation of thin granular sheets with
anisotropic shapes and show that the degree of anisotropy increases with the
aspect ratio of the jet's cross-section. Our results illustrate the liquid-like
behavior of granular materials during impact and demonstrate that a collective
hydrodynamic flow emerges from strongly interacting discrete particles. We
discuss the analogy between our experiments and those from the Relativistic
Heavy Ion Collider (RHIC), where similar anisotropic ejecta from a quark-gluon
plasma have been observed in heavy-ion impact.
