I found this video on YouTube while searching about fractals, and find it rather intriguing (and somewhat unsettling). Just thought some of you on the forum might be interested also. The poster has added a sound accompaniment of a descending Shephard's tone , which from what I read is a sound illusion that seems to continually decend in pitch while sort of staying where it is at the same time.
The video for some reason lasts for 10 hours! which would surely be a brain scrambler, but one does not need to view it all to get the point.