I know that much of Robert Monroe's later books are basically filtered by his own beliefs about the nonphysical state, though his experiences seemed pretty clean and pure without much religious trappings.

One common item in his books is the reference to beings as "curls". I notice that a complex spiral with a humanoid shape in the center, is a sort of logo for the Monroe Institute.

I'm wondering if this a direct perception that Robert saw of beings, sort of like a extremely complex knotting and twisting of an ethereal "rope".

I don't really know how to define what I'm even talking about here, as I have never "seen" it myself.

This might not be static but rather constantly moving or pulsating, changing in brightness or color. If there seems to be terminations of the spirals that lead out into space around the being, they could either just fade out and become invisible, or fan out and become part of the aura/shell around the being. 

This is just me making random guesses. I'm mainly just wondering if others who have been able to do astral projection, can they offer any insight on this, or am I totally off base.