Type-in from issue 19 (April 1987) of Amstrad Action.
Program is Listed at end of video.
Description from A.A. (with thanks to CPCRulez):
"David Brown of Sutton, West Midlands, has supplied you with an impressive pattern-producing program. There have been many such routines in the past - this one is rather exceptional. The patterns or designs are varied, complex and pleasant to view. Pressing the spacebar at any time will start a new pattern into life. This program will work only on the 664 or 6128."
https://www.youtube.com/watch?v=ntRF12k0TIU (https://www.youtube.com/watch?v=ntRF12k0TIU)
Links:
https://cpcrulez.fr/coding_src-list-graphic-patterns_mk_2.htm (https://cpcrulez.fr/coding_src-list-graphic-patterns_mk_2.htm)
https://www.cpc-power.com/index.php?page=detail&num=13030 (https://www.cpc-power.com/index.php?page=detail&num=13030)
https://www.cpcwiki.eu/index.php/AMSDOS#.7CUSER (https://www.cpcwiki.eu/index.php/AMSDOS#.7CUSER)
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.