SUGURU
Fill the grid so that each cell in a bold outlined cluster of cells contains the digits 1 and 2, a cluster of 3 cells contains 1, 2 and 3 and so on. No same digit should appear in any neighbouring cell, not even diagonally.
Fill the grid so that each cell in a bold outlined cluster of cells contains the digits 1 and 2, a cluster of 3 cells contains 1, 2 and 3 and so on. No same digit should appear in any neighbouring cell, not even diagonally.