Place scopes by certainty
Put a scope on the uphill side while the solution remains uncertain. Move it over the top once the team can explain the path, then down as it is built.
Update the reasoning
The dot alone is not a report. Pair a move with a note: what was learned, what remains risky, or what decision unlocked the work.
Review movement over time
Snapshots preserve the chart at meaningful moments. Comparing them exposes stalled scopes and gives planning discussions a concrete starting point.