PD program from 1986 by the author of Juggernaut and the much better known Tau Ceti series of games.
Some of the "trees" take a few minutes to complete so just fast forward when necessary.
https://www.youtube.com/watch?v=2sPxIxDbNY8&t=4s (https://www.youtube.com/watch?v=2sPxIxDbNY8&t=4s)
Links:
https://en.wikipedia.org/wiki/Pete_Cooke (https://en.wikipedia.org/wiki/Pete_Cooke)
https://www.wikiwand.com/en/Tau_Ceti_(video_game (https://www.wikiwand.com/en/Tau_Ceti_(video_game))
https://www.retrogamer.net/profiles/developer/pete-cooke/ (https://www.retrogamer.net/profiles/developer/pete-cooke/)
https://cpcrulez.fr/auteur-pete_cooke.htm (https://cpcrulez.fr/auteur-pete_cooke.htm)
https://www.cpc-power.com/index.php?page=detail&num=11589 (https://www.cpc-power.com/index.php?page=detail&num=11589)
https://www.cpc-power.com/index.php?page=staff&lenom=Pete%20COOKE (https://www.cpc-power.com/index.php?page=staff&lenom=Pete%20COOKE)
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.