def pos_letters(grid):
    # return a list composed of all the letters in grid with their positions
    list_letters = []
    for row in range(0, len(grid)):
        for column in range(0, len(grid[0])):
            if grid[row][column] not in {'#', ' '}:
                list_letters.append([row, column, grid[row][column]])
    return list_letters