Over time

1. Agree the interval and the span with the person: a month over a year, say. At most 24 points to start.
2. Read the same reading at each point: get_snapshot with the same network and parameters, and at set to each date. A final reading Petals already holds is reused, never read twice.
3. Count each with compute_figures, and say what changed: the top holder's share, the Nakamoto coefficient, who joined and who left.

Drawing the change on one flower waits for the visual protocol. Until then, draw the first and the last point, side by side, and say so.