Some solutions for 4X9
..0..0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..1..1
..0..0..0..0..0..0..0..1..3....0..0..0..0..0..0..0..1..7
..0..0..0..0..0..0..0..1..7....0..0..0..0..0..0..0..4..0
..0..0..0..0..0..0..0..6..7....0..0..0..0..0..0..0..4..5
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