: 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