Normal sudoku rules apply. Colour each cell in the grid one of two colours such that: Each colour forms a single orthogonally connected region; and no 2×2 block of cells is entirely one colour. The digits along each line sum to the same total (which must be deduced). Along each line, the colouring separates odd and even digits; that is, all odd digits on a line are one colour and all even digits are the other colour. Digits separated by a white dot are consecutive.