st piece of terminology.  In the neuron example, and in many
      dynamical systems, the dynamics were parameterized; in this case by a
      single parameter, $w$.  As we varied $w$, the fixed points of the system
      moved around.  In fact, if we increase $w$ through $w=1$, something
      dramatic happens - the system goes from having one fixed point to having
      three fixed points.  This is called a <em>bifurcation</em>.  This
      particular bifurcation is called a pitchfork bifurcation.  We oft