  In the framework of spatially extended dynamical systems, we present three
examples in which the presence of walls lead to dynamic behavior qualitatively
different from the one obtained in an infinite domain or under periodic
boundary conditions. For a nonlinear reaction-diffusion model we obtain
boundary-induced spatially chaotic configurations. Nontrivial average patterns
arising from boundaries are shown to appear in spatiotemporally chaotic states
of the Kuramoto-Sivashinsky model. Finally, walls organize novel states in
simulations of the complex Ginzburg-Landau equation.
