Normal sudoku rules apply. Shade some cells such that all shaded cells are orthogonally connected, all unshaded cells are orthogonally connected, and no 2x2 area is entirely shaded or unshaded. Values in a cage sum to the value in the corner of the cage. A digit in a shaded cell counts double its value to the cage total. Digits may not repeat in a cage (but values may, e.g. 4 and doubled 2 summing to 8.)