private static int[] randomEdgeLoc(int size) {
		int r, c;
		Random rand = new Random();
		int num = rand.nextInt(2);
		if (num == 0) { //random vertical edge coordinate
			r = rand.nextInt(size - 3) + 1;
			while (r % 2 == 0) 
				r = rand.nextInt(size - 3) + 1;// somewhere b/t row(1) to row(size-2)
			c = rand.nextInt(1) + 1;
			num = rand.nextInt(2);
			if (num == 0)
				c = 1;//left side
			else
				c = size - 2;//right side
		} else { //random horizontal edge coordinate
			c = rand.nextInt(size - 3) + 1;
			while(c % 2 == 0)
				c = rand.nextInt(size - 3) + 1;// somewhere b/t column(1) to column(size-2)
			num = rand.nextInt(2);
			if (num == 0)
				r = 1;//upside
			else
				r = size - 2;//downside
		}
		int[] edgeLoc = {r,c};
		return edgeLoc;	
	}//randomEdgeLoc()