Systems Biology is a new discipline aiming to understand the behavior of biological systems as it results from the (non-trivial, "emergent") interaction of biological components. In addition to analyzing existing biological networks to understand their function, it is also important to understand from the ground up what simple networks of interacting components "can do". That investigation can be carried out in abstract "artificial" frameworks, as long as the ground rules are kept close enough to the ones of biochemistry. We discuss some biologically inspired networks that are characterized by simple components, but by complex interactions. Subtle and unexpected behavior emerges even from simple circuits, and yet stable behavior emerges too, giving some hints about what may be critical and what may be irrelevant in the organization of biological networks.
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