A lot of that stuff is always there - just think of the hundreds of optical illusions that can be constructed! - but until it's connected with an emotional experience during a trip, the brain doesn't single it out.

The effect that jumped out at me was focusing at a spot on the floor while standing up and turning. It creates the momentary impression of a spiral pattern in my perception. Especially with a dot-like pattern on the floor :)

Also, if you like rainbow halos, you might also like Shock Diamonds: https://www.google.com/search?q=shock+diamonds&source=lnms&t...