[comdpa]

12-5-1 Basic Motion lists Rhythm as a component (in fact it's listed as a component for an abbreviated version of the Basic Motion). I'm not sure I understand why it's listed at all. If Rhythm is "holding both Lever Assemblies to the same basic RPM throughout the stroke...", why would we be concerned about rhythm at this stage when #3 accumulator is zero? It seems like it should first be introduced with the Acquired Motion. What am I missing here?

The simple answer is that in every stroke no matter its length, there is a hinge action and even with zero #3 accumulator, you can still bend your left wrist.