synchronized public void setsize (int s)
	// set the board size
	// clears the board !!!
	{
		if (s < 5 || s > 59) return;
		S = s;
		P = new Position(S);
		number = 1;
		Node n = new Node(number);
		n.main(true);
		lasti = lastj = -1;
		T = new SGFTree(n);
		Trees.setElementAt(T, CurrentTree);
		Pos = T.top();
		makeimages();
		showinformation();
		copy();
	}