public void TraceBackwards(Line line, Vector2Int finalpos)
{
var startpos = line.GetNode(0);
var pos = finalpos;
line.Clear();
while (pos != startpos)
{
Set(pos, line.id);
line.AddNode(pos);
pos = GetParent(pos);
}
Set(pos, line.id);
line.AddNode(pos);
}
