Connect each white circle with a black circle by a horizontal/vertical line. Lines cannot cross. Each circle is the endpoint of exactly one line.
Goal: Connect each white circle to a black circle by drawing a single horizontal/vertical line.
Rules:
• Click an edge between two cell centers to draw/erase it.
• Each line may use 0, 1, or more 90-degree turns.
• Lines cannot cross each other.
• Lines cannot pass through any circle (only as endpoints).
• Each white circle is the endpoint of exactly one line.
• Each black circle is the endpoint of exactly one line.
Controls:
• Click an edge to draw/erase it.
• Draw mode: click adds edges. Erase mode: click removes.
• Keys: H hint, R restart, Enter check, Esc menu.