Two parties. Rising water.
Bring amber A and violet B to their matching summit flags. Select a party, then tap a neighboring dry cell. Every move raises water, and both parties must stay dry. Two shared drainage charges lower water by 0.9 m but each uses a turn.
Numbers are elevation in metres. Blue cells are flooded. Gold and purple flags are safe summits. The next water level is shown before every move.
Plan the crossing.
- Turn
- Water now
- Water after next move
- Drain charges
- Safe parties
Study the low saddles. Move the vulnerable party before water reaches it.
Reading the map
A cell must be dry both before and after your step. Switching parties is free. Reaching a matching flag protects that party from future water. Use undo to compare a different route.
Contour computation & source
d3-contour’s marching squares computes land polygons from the 7×7 elevation field at the current water threshold. The same polygon point-containment decides legal cells and drowning, so the drawn contour and game geometry share one source. The terrain texture is generated art. Original rescue puzzle, six synthetic valleys; not a hydrological forecast.
d3-contour, Mike Bostock, ISC license, pinned8a3b95a. Explicit-threshold adapter removes unused automatic threshold dependencies; editable modules and license bundled.