We present numerical simulations of a simplified model for the ring ca
vity device in the case of round-trip time equal to the atomic radiati
ve lifetime. Real pattern effects are of primordial importance, especi
ally in small systems where the boundary conditions seem the key for t
he pattern selection. For a plane-wave input, our system displays not
only hexagons, as in the mean-field model, but also stationary rolls,
squares and octagons with a weakly chaotic structure. All these struct
ures are also obtained in the case of bell-shaped input profile with l
arge aspect ratio; they even appear regular and wonderful, as if bound
ary effects stabilize them.