They predict obstacles on the way to achieve intended goals, so it is advisable to be patient and smart in order to avoid them. Lying in between dunes evidences withdrawal during difficult moments, as well as outright emotional or economic losses.
[1]1. Flexibility, ability to change.
2. Protection or obstacle to spiritual life.
[2]Memories of travels; temporary. Something is fizzling out. Quicksand, Sand, Beach.
[3]