Strong nonlinear optical effects and optical pattern-forming systems can be designed with the optical system architectures introduced here on the basis of large-scale arrays of optoelectronic feedback circuits. Experiments were performed with a liquid-crystal television panel as a large-scale array of phase modulators and a CCD camera as a photoarray. By synthesizing various nonlinearities and using controllable spatial coupling, we obtained a variety of transversal optical patterns, localized states, waves, and chaotic regimes.