Keywords: Jet, layer, potential vorticity, beta-plane, stratified turbulence, Cahn-Hilliard equation, negative viscosity Abstract: I'll discuss two examples of uniformly forced turbulent flows in which quasi-steady structures spontaneously form. This results in the intensity of turbulence becoming spatially inhomogeneous on length scales larger than those of the eddies i.e., as argued by Owen Phillips in 1972, a spatially homogeneous turbulent flow may be subject to a large-scale instability. The first example is stirring a fluid with strong gravitational stability due to, for example, dissolved salt. The resulting stratified turbulence produces well-mixed layers with uniform density, separated by strongly stable steps in density. The second example is the formation of zonal jets in forced-dissipative beta-plane turbulence. I'll discuss the prospects of understanding these systems using models related to the Cahn-Hilliard equation.