Message:There would need to be a simple item and a log book. A knotted cord would have the utility. Measure point to point moves, vector magnitude and angle. I also like an entranced slave or savant acting like a recorder, describing to the nth detail what directions the party has gone. The true purpose of the Minstrel would be to encode the expedition's progress in a song for ease of memory.
Yet part of me thinks that if a delver ever came upon a perfectly square, reinforced and plastered room, he would take a step back and brick the entrance closed. Whatever lives there is magnificent, obsessive and insane. I have a dozen plus rooms (closets, crawlspaces, hidey-holes, overhangs, garages, sheds) in my home and none of them have square corners. Not to that precision.
Yours,
IronRed
15-Jan-2023