{
fprintf(stderr, "[%d] (%d,%d)->(%d,%d) ", (int)s->nr, s->a.x, s->a.y, s->b.x, s->b.y);
fprintf(stderr, " dx:%d dy:%d k:%f dx/dy=%f fs=%p\n", s->delta.x, s->delta.y, s->k,
{
fprintf(stderr, "[%d] (%d,%d)->(%d,%d) ", (int)s->nr, s->a.x, s->a.y, s->b.x, s->b.y);
fprintf(stderr, " dx:%d dy:%d k:%f dx/dy=%f fs=%p\n", s->delta.x, s->delta.y, s->k,