: Test for source tree numbering (A?): Level A (A*1?): Level B (A*2?): Level B (A*2*1?): Level C (A*3?): Level B (A*3*1?): Level C (A*3*1*1?): Level D (B?): Level A (B*1?): Level B (B*1*1?): Level C (B*1*1*1?): Level D (B*1*1*1*1?): Level E (C?): Level A (C*1?): Level B (C*1*1?): Level C (C*1*1*1?): Level D (C*1*1*1*1?): Level E (C*1*1*2?): Level D (C*1*1*2*1?): Level E (C*1*2?): Level C (C*1*2*1?): Level D (C*2?): Level B