Also look into Bruce Cathie's World Grid. Seems to be ley lines through a different perspective based on mathematics and harmonics. Different harmonics would essentially be different grids overlaid. That could explain the appearance of shifting ley lines. /spitballing
https://criticalbelievers.proboards.com/thread/4093
http://www.worldgrid.net/1492/geodetic-conversions-for-magnetic-field-of-the-earth/
https://www.bibliotecapleyades.net/ciencia/antigravityworldgrid/ciencia_antigravityworldgrid04.htm