: Test for source tree numbering *%A+?: Level A *%A|a+?: Level B *%A|b+?: Level B *%A|b|a+?: Level C *%A|c+?: Level B *%A|c|a+?: Level C *%A|c|a|a+?: Level D *%B+?: Level A *%B|a+?: Level B *%B|a|a+?: Level C *%B|a|a|a+?: Level D *%B|a|a|a|a+?: Level E *%C+?: Level A *%C|a+?: Level B *%C|a|a+?: Level C *%C|a|a|a+?: Level D *%C|a|a|a|a+?: Level E *%C|a|a|b+?: Level D *%C|a|a|b|a+?: Level E *%C|a|b+?: Level C *%C|a|b|a+?: Level D *%C|b+?: Level B