Conclusion Stationary convection:
	In the absence of a toroidal flow component: - tracer move on the surface of torii - the symmetry planes of the temperature field confine the torii - material is communicated between the boundaries and the interia of the cell A torodial flow component - can be generated by a finite Prandtl number or by    boundary conditions - this leads to the coexistence of regular and chaotic    mixing regions - the mixing efficiency is greatly enhanced by these regions