Normal sudoku rules apply.Some cells (to be located by the solver) are doublers, and have a value equal to double their digit.The even-valued cells (including doublers) form a single orthogonally connected area. Every even cell must see at least one doubler in a straight line horizontally or vertically (odd-valued cells block the view). Doublers must not see each other.The values of cells in a cage sum to the total in the corner of the cage (if given). Digits may not repeat in a cage (though values may repeat).