Alignment guides shown while dragging. A dragged element’s features (edges,
centers, pin stubs, or a single corner) are matched against the same features
of every other shape; each like-kind coincidence draws a thin line spanning
the aligned pair, drawn over the diagram so a center guide (which runs
through the opaque shapes it aligns) stays visible.
Moving shapes: the per-kind moves, the collision rules that gate them, and
the group move that keeps a selection’s relative layout — plus the waypoint
reconciliation each move owes the routes that touch it.
Route (re)solving for a level: the closed-graph solver every commit and
every drag/resize preview goes through, the per-leg reconstruction that
rebuilds a route’s geometry from its stored corners, and the rip-up/reroute
entry points.