unsigned first_on_last_line = (size() - 1) - (size() - 1) % width;
DEBUG4("torus size = %u ; width = %u ; height = %u ; foll = %u",
unsigned first_on_last_line = (size() - 1) - (size() - 1) % width;
DEBUG4("torus size = %u ; width = %u ; height = %u ; foll = %u",