[ B ] { offset: 2,0; origin: A; size: 2,1; }
[ C ] { offset: 2,-2; origin: B; }
[ A ] --> { end: south, 0; start: south; } [ C ]
[ B ] --> { end: south, 0; start: south; } [ C ]
[ B ] --> [ U ]
[ B ] { offset: 2,0; origin: A; size: 2,1; }
[ C ] { offset: 2,-2; origin: B; }
[ A ] --> { end: south, 0; start: south; } [ C ]
[ B ] --> { end: south, 0; start: south; } [ C ]
[ B ] --> [ U ]