Maestro n° 103 : Page 57 - Gr 54
L5C6 =6= L7C6 -6- L7C8 =6=8= L7C8 -8- L8C9 =8= L8C3 -8- L6C3 =8= L6C2 -8-4- L6C2 =4= L6C5 donc L5C6 ≠ 4 et L6C5 ≠ 6