Maestro n° 104 : Page 87 - Gr 84
L5C9 -4- L4C7 =4=9= L4C7 -9- L4C2 =9= L1C2 -9-6- L1C2 =6= L1C8 -6- L6C8 =6= L5C9 donc L5C9 ≠ 4