Shown here is the wave function of a cylinder with an oscillating cross section in the shape of a quadrupole. In the undeformed circle, the angular momentum quantum number is 68, the wavelength in the cavity is about 14 times smaller than the radius. The index of refraction of the cavity is 1.55 (i.e. that of glass). Classical phase space structure here causes the emission at high deformation to violate intuitive expectations: The light does not come out tangential to the points of highest curvature. The phase space structure is also reflected in the internal wave function.