The support point is a point of rest. The two extensions to right and left are points of rest where outward moving entropic energy is arrested then converted into inward moving syntropic force.

Figure 8.9 - Four Fundamental Motions of a Pendulum

See Also

double vibration
Figure 8.11 - Four Fundamental Phases of a Wave
oscillation
pendulum
Ramsay - PLATE IV - Oscillation and Vibration
Ramsay - The New Way of Reckoning a Vibration
single vibration
string
vibration