public synchronized void varleft ()
	// one variation to the left
	{
		State = 1;
		getinformation();
		ListElement l = Pos.listelement();
		if (l == null) return;
		if (l.previous() == null) return;
		TreeNode newpos = (TreeNode)l.previous().content();
		goback();
		Pos = newpos;
		setnode();
		showinformation();
		copy();
	}