grandmaitre n° 17 : Page 62 - Grille 49
L2C1 =3=5= L2C1 -5- L2C4 =5=6= L2C4 -6- L2C7 =6= L1C7 -6-3- L1C7 =3= L1C23 donc L3C13 ≠ 3