Yes, I found that link also, but alas the website from Descarta2D is out of the air. It's a bit outdated software of course , but I would like try it.
The major developer was Denis Monasse, a French mathematician.
I am also retired : bicycling, gardening are my daily activities. Evenings are filled with some studying in Mathematics.
Thank you for your answer.
Chiel Geeraert