def add_new_tile_at_position(grid, position, value):
    """
    Puts a tile in the game grid, given the coordinates (x,y) of the tile.

    :param grid: The game grid
    :param position: (x, y) tuple with the position
    :param value: The value of the tile (its symbol, for instance)
    :return: Game grid with a new tile with coordinates (x,y)
    """
    grid[position[0]][position[1]] = value

    return grid