public void createMap()
	{		
		int random, x, y;
		tiles = new Colour[size][size];
		Random rand = new Random();
		
		for (int i = 0; i < tiles.length; i++)
		{
			for (int j = 0; j < tiles[i].length; j++)
			{
				random = rand.nextInt(5);

				if (random == 0)
					tiles[i][j] = Colour.BLUE;	//probability of blue tile is 1/5
				else 
					tiles[i][j] = Colour.GREEN;
			}
		}		
		//assign random coordinates to treasure
		x = (int)(Math.random()*(size-1))+1;
		y = (int)(Math.random()*(size-1))+1;
		tiles[x][y] = Colour.YELLOW;	
	}