just sharing this thing I made 2 years ago. Only single function, but i think its quite clever how it can path find vertically so I'm putting it here and hope you can put it to good use. It's always been my dream to make a smart turtle T.T

[Requires GPS]

Process of goto function
-get position w/ gps
-move forward
-recheck position to determine face direction
-go to x (vertical pathfinding)
-go to z (vertical pathfinding)
-goto y (force to dig blocks up/down)

Plans I had in mind on where to use it:
-check block every movement to scan land surface and run functions.
-make turtle follow you (possible now with portable computer)
-scan land surface and display it in monitor layer by layer

It can walk very well in natural lands, but not the best maze solver for complex vertical mazes.

Pastebin Link