"I have made a simple flicker machine. You look at it with your eyes shut and the flicker plays over your eyelids. Visions start with a kaleidoscope of colours on a plane in front of the eyes and gradually become more complex and beautiful, breaking like surf on a shore until whole patterns of colour are pounding to get in. After a while the visions were permanently behind my eyes and I was in the middle of the whole scene with limitless patterns being generated around me. There was an almost unbearable feeling of spatial movement for a while but it was well worth getting through, for I found that when it stopped I was high above earth in an universal blaze of glory. Afterwards I found that my perception of the world around me had increased very notably. All conceptions of being dragged or tired had dropped away..."
January 1, 1970
https://en.wikiquote.org/wiki/Kaleidoscope