## Mechanical model The Ptolemaic Clock treats what appears on screen as a six-rotor mechanism rather than as three painted hands. Hour, Minute, and Second each consist of a **Hand** paired with a **Bezel**. The relationship between the two members of a lane determines the time indicated by that lane. The model is divided into two complementary parts: - **[Elements](elements.html)** describes the six physical rotors and the positions they occupy. - **[Movement](movement.html)** describes how each rotor receives a target trajectory and how that trajectory can be transformed. This distinction is important throughout the application. Position changes the pose of the mechanism; Drive defines where a rotor is being asked to go; Motion transforms that request locally; and Epicycle moves a bezel's center without replacing its rotational trajectory. The framework shell owns navigation, themes, typography, panels, and other interface services. The Clock application owns this mechanical model and its state. That boundary does not alter the mechanism, but it keeps the model independent of the site interface around it.