정규식을 사용하여 ASCII '이미지'에서 세 개의 연속된 'X' 문자의 수직 형태를 계산하려면 어떻게 해야 합니까?

(?xm)
^                        # Beginning of line
(?:
    .                    # Any character except newline
    (?=                  # Lookahead
        .*+\n            # Move to next line
        ( ?+ . )       # Add a character to capturing group 1
        .*+\n            # Next line
        ( ?+ . )       # Add a character to capturing group 2
    )
)*?                      # Repeat as necessary
X .*+\n                  # X on first line, advance to next line
?+                     # If capturing group 1 is defined, use it
X .*+\n                  # X on second line, advance to next line
?+                     # If capturing group 2 is defined, use it
X                        # X on third line

^
(?:
    (?:                   # Match .+? characters
        .
        (?=               # Count the same number on the following two lines
            .*+\n
            ( ?+ . )
            .*+\n
            ( ?+ . )
        )
    )+?
    (?<= X )              # Till the above consumes an X
    (?=                   # That matches the following conditions
        .*+\n
        ?+
        (?<= X )
        .*+\n
        ?+
        (?<= X )
    )
    (?=                   # Count the number of matches
        .*+\n
        ( ?+ . )        # Number of matches = length of 
    )
)*                        # Repeat as long as there are matches on this line
.*\n?                     # Remove the rest of the line