Yin-Yang: shade some cells so that all shaded cells are orthogonally connected, all unshaded cells are orthogonally connected, and no 2x2 region is entirely shaded or unshaded. In addition, place a digit (from 1 to 9) in every cell with an arrow. This digit is the total number of shaded cells in the indicated direction (including the cell itself, if it is shaded). No two shaded cells can contain the same digit, and no two unshaded cells can contain the same digit. (However, the same digit may occur once shaded and once unshaded.) Cells without arrows do not contain digits.