I listened to all the kasina fire practice recordings - very interesting, and just occured to me it may be related to cave art, in that you are spending a lot time observing internal visual phenomena.

There  is a theory that the various dots and squigggles painted in caves, often directly onto other paintings of animals etc., are reproductions of naturally occuring patterns produced by the visual system. It's been suggested that these may have been traced directly onto the rock.

Would kasina be related to this, and is there anything in buddhist lore that would relate to this ?

The guys doing the kasina retreat were chasing a deliberately fire induced effect. Why not the natural ones - what would be the difference and has this been tried ?

Given the meditative high reported from the retreat, it would seem there is a reward mechanism for pursuing concentration on visual effects that's different from performing sympathetic hunting magic. I don't know if hunting magic is still an extant theory but could these be combined ? Is there anything in buddhist practice that combines wish fulfillment and absorption practice on internal visuals - siddhi wise ? Many people attempt such magic nowadays but I've never heard of entoptic visuals being deliberately involved.

Thoughts, O wise ones ?