PICK D3 has been doing similar since... well, a very long time. It uses chr(254), chr(253) and chr(252) for the varying depths of records. I always rather enjoy

PICK D3 has been doing similar since... well, a very long time. It uses chr(254), chr(253) and chr(252) for the varying depths of records. I always rather enjoyed working with it in the 2000s. Elegant in its simplicity, functionally practical (for the workloads we had at the time at least)