1. Draw a single loop that connects the centers of the grid cells. The loop may not pass through any cells which contain arrows. The loop may only travel horizontally or vertically, and never diagonally (so all turns are of 90 degrees). The loop may only turn at the centers of the grid cells. The loop may not cross itself or branch off. In other words, the interior of the loop will be a single polygon.
2. Any cell that does not have an arrow and which is not part of the loop must be shaded in black. No other cells may be black. No two black cells may share an edge.
3. A cell containing a number and an arrow represents how many black cells are in the row or column pointed at by the arrow.
