These "dots appearing only while (not) focused" are known as "extinction illusions", namely "25 - Appearing Dots" is "McAnany's type" [1], and "26 -

These "dots appearing only while (not) focused" are known as "extinction illusions", namely "25 - Appearing Dots" is "McAnany's type" [1], and "26 - Disappearing Dots" is known as "Ninio's type" [2], according Akiyoshi Kitaoka's materials. (I have recreated them too few years ago [3][4], before getting to the source.) [1] https://www.psy.ritsumei.ac.jp/akitaoka/kieru3e.html#:~:text=McAnany%27s%20typeMcAnany https://www.psy.ritsumei.ac.jp/akitaoka/kieru3e.html#:~:text... [2] https://www.psy.ritsumei.ac.jp/akitaoka/kieru3e.html#:~:text=Ninio%27s%20type https://www.psy.ritsumei.ac.jp/akitaoka/kieru3e.html#:~:text... [3] https://codepen.io/myf/full/XjdmJy https://codepen.io/myf/full/XjdmJy ( scintillation warning) [4] https://codepen.io/myf/full/jMqoMW https://codepen.io/myf/full/jMqoMW ( scintillation warning)