It takes practice. My elementary school had these on the bookshelves we used for indoor recess, so I spent several hours just staring and staring, hoping for something to happen. Eventually due to the boredom of the staring, my eyes defocused naturally and I saw enough of an effect to realize that was the whole trick. Then from there I tried to gain conscious control of my focus depth while adjusting the viewing distance, until finally I fully got it :)
janus2@lemmy.zip 4 weeks ago
www.math.brown.edu/tbanchof/…/stviewing.html
It takes practice. My elementary school had these on the bookshelves we used for indoor recess, so I spent several hours just staring and staring, hoping for something to happen. Eventually due to the boredom of the staring, my eyes defocused naturally and I saw enough of an effect to realize that was the whole trick. Then from there I tried to gain conscious control of my focus depth while adjusting the viewing distance, until finally I fully got it :)