# Motion language

Motion is documented by **meaning**, not by CSS.

Ask: what does this movement communicate?

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## Appear

- **Meaning:** something that was absent becomes present
- **Use:** new events on a timeline; an output that did not exist at t0
- **Not:** fading a hero for polish
- **Seen in:** progressive timeline events; process-diagram output C

## Reveal

- **Meaning:** something present was occluded; now it can be read
- **Use:** labels at zoom threshold; callouts; glosses
- **Seen in:** spatial map fine labels; annotation callouts

## Assemble

- **Meaning:** a whole is constructed from parts in order
- **Use:** diagrams that must not be shown complete too early
- **Seen in:** scroll narrative staged diagram

## Propagate

- **Meaning:** signal or influence moving through a system
- **Use:** processes, neural signaling, information flow, network activation, ECG as a *pattern* (not a product)
- **Seen in:** process diagram token travel; feedback-loop error → effector

## Flow

- **Meaning:** continuous movement along a path
- **Use:** circulation, pipelines
- **Difference from propagate:** flow is the medium; propagate is the signal

## Drift

- **Meaning:** a variable leaves equilibrium
- **Use:** disturbance, uncertainty, wandering attention
- **Seen in:** negative-feedback variable after disturb

## Expand / Collapse

- **Meaning:** a region’s capacity changes; identity stays
- **Use:** disclosure, dossiers
- **Seen in:** knowledge-graph dossier

## Transform

- **Meaning:** state change of the same entity
- **Use:** processor activation; comparison wipe
- **Seen in:** process-diagram B fill; comparison clip

## Connect / Separate

- **Meaning:** a relation is asserted or withdrawn
- **Use:** graph focus; comparison property highlight
- **Seen in:** neighborhood edges; matrix row → diagram parts

## Follow

- **Meaning:** accompaniment; the visual keeps time with the reader
- **Use:** sticky diagrams, playheads
- **Seen in:** scroll narrative sticky stage; timeline playhead

## Pulse

- **Meaning:** a repeating reminder of liveness or warning
- **Use:** alarms, heartbeat — sparingly
- **Anti-pattern:** pulsing everything that is “active”
- **Not yet used** in seed experiments (on purpose)

## Settle

- **Meaning:** return to rest after change
- **Use:** after inertia pan; after a control loop reaches setpoint
- **Seen in:** infinite-canvas coast; feedback loop return to 37.0