Maestro n° 101 : Page 82 - Gr 79
L1C5 -4- L3C4 =4= L7C4 -4-7- L7C4 =7= L2C4 -7-9- L2C4 =9= L2C5 -9-3- L2C5 =3= L1C5 donc L1C5 ≠ 4