$pattern =~
    /
        ^
        _*                  # 0 or more underscores to start
        (
            (\d*|#*|\**)+   # Any combo of digits, #s, or *s
            (\[\d+\-\d\])?  # Maybe a [x-y]
        )
        (X*\.?\!?)          # Zero or more Xs, and maybe a . or !
        $
    /gx;