static ArrayList<Pair> surround(Pair start) {
   // 	System.out.printf("start is (%d, %d)", start.x, start.y);
    	ArrayList<Pair> prlist = new ArrayList<Pair>();
    	for (int i=0; i<4; i++) {
    		Pair tmp0 = new Pair(start);
    		Pair tmp;
    		if (i==0) {
    			//if (start.x>0) {
    			tmp = new Pair(tmp0.x-1,tmp0.y);
    	//		if (!PairtoPoint(tmp).water)
    			prlist.add(tmp);
    		//	}
    		}
    		if (i==1) {
    			//if (start.x<size-1) {
    			tmp = new Pair(tmp0.x+1,tmp0.y);
    		//	if (!PairtoPoint(tmp).water)
    			prlist.add(tmp);
    			//}
    		}
    		if (i==2) {
    			//if (start.y>0) {
    			tmp = new Pair(tmp0.x, tmp0.y-1);
    			//if (!PairtoPoint(tmp).water)
    			prlist.add(tmp);
    			//}
    		}
    		if (i==3) {
    			//if (start.y<size-1) {
    			tmp = new Pair(tmp0.x, tmp0.y+1);
    			//if (!PairtoPoint(tmp).water)
    			prlist.add(tmp);
    			//}
    		}
    		
    	}
    	
    	return prlist;
    }