U2010046

def create_chessboard(rows, cols):
    chessboard = []
    for row in range(rows):
        row_data = []
        for col in range(cols):
            # Alternating between dark and light squares
            if (row + col) % 2 == 0:
                row_data.append('.')
            else:
                row_data.append(' ')
        chessboard.append(row_data)
    return chessboard

def display_chessboard(chessboard):
    for row in chessboard:
        print(" ".join(row))

# Define the size of the chessboard
rows = 13
cols = 13

# Create and display the empty chessboard
chessboard = create_chessboard(rows, cols)
display_chessboard(chessboard)