Optical illusions slideshow from 2001 by the Flower Corp group.
https://www.youtube.com/watch?v=PI5VxmkhAJQ (https://www.youtube.com/watch?v=PI5VxmkhAJQ)
Links:
https://www.cpcwiki.eu/index.php/Flower_Corp (https://www.cpcwiki.eu/index.php/Flower_Corp).
https://www.cpc-power.com/index.php?page=detail&num=8118 (https://www.cpc-power.com/index.php?page=detail&num=8118)
https://cpcrulez.fr/info-flower_corp.htm (https://cpcrulez.fr/info-flower_corp.htm)
https://en.wikipedia.org/wiki/M._C._Escher
Not emulated - original hardware and software.
Please note that the aspect ratio for this YouTube video is 16:9 but the CPC monitor
has an aspect ratio of 4:3 so you may wish to adjust your viewing device accordingly.