Think drug-induced hallucinations, and the whirly, spirally, tunnel-vision-like patterns of psychedelic imagery immediately spring to mind. But it's not just hallucinogenic drugs that conjure up these geometric structures. People have reported seeing them in near-death experiences, following sensory deprivation, or even just after applying pressure to the eyeballs. So what can these patterns tell
us about the structure of our brains?
In these days of debates on climate change we're often reminded of that other great clash between science and authority, the staunch refusal by the Catholic church to accept that the Earth moves around the Sun.