W4
i520.175.23
W4 r5c6 ISN'T 9: 9 in columns 1,5,8,9 form a 4x4 closed circuit r1c2r1c3r5c6 r1c2#9r1c3#9r5c6#9
W4 r1c1r6c1r3c5r5c5r1c8r3c8r5c8r3c9r6c9
W4
i520.204.20
W4 r9c8 ISN'T 7: 7 in columns 1,3,4,9 form a 4x4 closed circuit r3c7r9c8 r3c7#7r9c8#7
W4 r2c1r3c1r8c3r9c3r2c4r3c4r8c4r2c9r9c9