## Drive **Drive** establishes the target trajectory of each physical Hand and Bezel before Motion is applied. The Hour, Minute, and Second lanes share the same Drive vocabulary, but every rotor retains its own definition unless it is a Time slave. ### Clock **Clock** drives a rotor at the natural rate of its lane. Hour follows the clock's hour period, Minute its minute period, and Second its second period. Direction is physical **CW** or **CCW**. Reversing direction re-anchors the rotor at its current pose so the change does not cause an instantaneous jump. ### Fixed **Fixed** holds one authored pre-Motion position. Entering Fixed captures the rotor's current pre-Motion position. The Hour, Minute, Second, and Angle fields are synchronized ways of editing that same position. Fixed applies at the Drive boundary only. A rotor can therefore have a fixed Drive target while a later Motion stage still moves the rendered rotor around that target. ### Free **Free** drives the rotor with an authored speed, direction, and phase. Speed is expressed relative to the natural revolution period of the lane: Hour uses revolutions per 12 or 24 hours, Minute uses revolutions per hour, and Second uses revolutions per minute. ### Coupled **Coupled** derives a rotor's Drive from another Hand or Bezel. The relationship is controlled by ratio, same/opposite direction, and phase. The source may be anywhere in the six-rotor graph except where that choice would create a circular dependency. Synchronization actions align coupled rotors without changing the authored coupling definitions. Coupling supplies only the destination rotor's Drive target; it does not import the source rotor's local Motion settings. ### Time slave A **Time slave** gives up independent Drive authority. Its pre-Motion target is derived from the other element in the same lane so that the Hand/Bezel relationship indicates the configured time. A lane can have at most one Time slave. A Time-slave relationship is a structural guarantee of the lane's time relationship, but it is not the only way a lane can happen to show correct time. Two independently driven rotors can also agree with wall time when their resolved Drive positions maintain the required relative angle. Choices that would close a dependency cycle are unavailable and are rejected without changing the existing Drive graph. ## Motion **Motion** reshapes a rotor locally after Drive has resolved its target. Every Hand and Bezel has its own four-stage pipeline, and the stages always run in this order: **Drive → Timing → Advance → Response → Modulation** ### Timing **Continuous** preserves the Drive timebase. **Stop-to-go** compresses active travel into the moving portion of a cycle and holds at the end, producing a repeating run-and-pause pattern. Timing changes *when* the trajectory progresses without yet quantizing its positions. ### Advance **Smooth** passes the Timing trajectory through. **Step** samples it at a fixed time interval. **Ratchet** quantizes the target to angular teeth. Advance therefore controls *how* the timed target progresses through positions. Because Timing and Advance are distinct stages, combinations such as Stop-to-go + Step and Stop-to-go + Ratchet remain meaningful. ### Response **Direct** follows the Advance target exactly. **Spring** treats the target as an equilibrium and lets the physical rotor approach it dynamically. Tension controls stiffness; Bounce controls how much oscillation survives, allowing overshoot and ring-down. ### Modulation **None** adds no further offset. **Pendulum** adds a periodic angular swing with an authored amplitude and period. **Drift** adds a slower cyclic displacement. Modulation is last, so it acts around the result of Response. Motion never propagates through a coupling or Time-slave relationship. Those relationships resolve Drive first; the destination rotor then applies its own local Motion pipeline. ## Epicycle **Epicycle** is a bezel-only stage applied after the bezel's rotational Drive and Motion have been resolved. It moves the bezel's center around the main clock center while leaving the bezel's rotational trajectory intact. **Radius** sets the orbital displacement, **Period** sets one orbit duration, and **CW / CCW** sets orbital direction. Hour, Minute, and Second bezels each retain their own epicycle configuration, and copy actions can propagate individual parameters or a complete epicycle configuration between lanes. The **Path preview** is diagnostic rather than mechanical. It draws the recent orbital trace and can adjust trace thickness/transparency or fade the rest of the clock for inspection. These presentation settings do not change the epicycle mechanism itself.