: Test for source tree numbering 1: Level A 1+1: Level B 1+2: Level B 1+2-1: Level C 1+3: Level B 1+3-1: Level C 1+3-1+1: Level D 2: Level A 2+1: Level B 2+1-1: Level C 2+1-1+1: Level D 2+1-1+1-1: Level E 3: Level A 3+1: Level B 3+1-1: Level C 3+1-1+1: Level D 3+1-1+1-1: Level E 3+1-1+2: Level D 3+1-1+2-1: Level E 3+1-2: Level C 3+1-2+1: Level D 3+2: Level B