Coooeee!

< sherrat thinks the decorations on grooved ware and some rock art may be 'entoptic' - a range of constant forms widely - and still - produced under trance conditions. >

Highly debatable, it's gotta be said - and is very much substance-dependant. In countless experiments I've done with some of the suggested entoptic-producing plants, utilising various techniques, such visionary content is initial and short-lived. The primary psychedelic visual material is non-entoptic for most of the European plants.

Cheers - Paul