Probably deserves a "2009" in the title. The 2015 HN discussion had only one comment, but that comment had an interesting link.<p><a href="https://news.ycombinator.com/item?id=10397619" rel="nofollow">https://news.ycombinator.com/item?id=10397619</a>
Fascinating stuff. I've often thought that the nature of hallucinations - geometric or otherwise - must have lots to tell us about the workings of the brain. From a mechanistic viewpoint all our experiences (hallucinations included) supervene on brain structure, therefore these common geometric hallucinations likely reflect some fundamental structure of the brain.<p>On a related note, here's an interesting article from 2015 about encrypting information so that only people who are on LSD can read it: <a href="https://qualiacomputing.com/2015/05/22/how-to-secretly-communicate-with-people-on-lsd/" rel="nofollow">https://qualiacomputing.com/2015/05/22/how-to-secretly-commu...</a>
"But it's not just hallucinogenic drugs like LSD, cannabis or mescaline that conjure up these geometric structures."<p>The article seems to be interesting, but this start turned me off a bit, as it is wrong. Cannabis is not hallucinogenic. When you get hallucinations from cannabis, then you might have a problem called psychosis...