Mechanic Preview
Surface vessels can only travel where the water is at the same level.
Three locks sit at progressively lower elevations between four water segments. Water flows in from the upper-left and out the lower-right. Each closed lock dams the water against it — the segment upstream rises until it spills over the lock's top. Each open lock equalizes the segments on either side.
Two boats float on the water surface and can only navigate horizontally where the water is at one consistent level — either through an open lock or across the top of a closed lock if the water has risen above it on both sides. Toggle the locks (click a lock or use the buttons below) and use each boat's arrow controls to chart a path.