## A simple clock A conventional clock has three hands moving against a fixed face. The Ptolemaic Clock starts from the same familiar idea but separates each lane into two physical rotors: an Hour, Minute, or Second **hand** and its corresponding **bezel**. The time shown by a lane is determined by the angular relationship between the two. In the canonical arrangement the hands behave like ordinary clock hands and the bezels provide their reference frames. Because both members of a lane are independent rotors, however, either one can move while the pair continues to indicate time. The Clock page exposes all six rotors and lets their positions, visibility, movement, and appearance be inspected directly. The application is therefore both a clock and a mechanical model of a clock. Start with the [Clock](clock/) page if you want to manipulate it immediately, or continue with [How it works](how-it-works/) for the underlying model. ## Drive **Drive** establishes the target trajectory of every hand and bezel before any local Motion is applied. A rotor can follow natural clock time, hold a fixed position, run freely at an authored rate, or derive its trajectory from another rotor. A lane can also designate one member as a **Time slave**, making that rotor follow its lane partner so that their relative angle continues to indicate the configured time. This separation makes ordinary timekeeping a mechanical relationship rather than a hard-coded special case. The two rotors of a lane may move together, oppose one another, run at different rates, or be linked into a larger six-rotor dependency graph while the application keeps the relationships explicit. The [Movement](how-it-works/movement.html) page describes Clock, Fixed, Free, Coupled, and Time-slave Drive in detail. ## Complex motions Drive is only the beginning of the movement pipeline. Each physical rotor has four independent, local **Motion** stages applied in order: **Timing → Advance → Response → Modulation**. These stages can introduce stop-and-go timing, stepping or ratcheting, spring response, pendulum swing, and drift without changing the authored Drive relationship beneath them. Bezels have one additional final stage: **Epicycle**. An epicycle moves the bezel's center around the main clock while the bezel continues to rotate according to its own Drive and Motion trajectory. Because the stages are explicit and ordered, complicated motion can be built from simple operations and inspected one stage at a time. The mechanics table on the Clock page exposes the same pipeline either as live values or as compact formulas.