Now all you need do is write "lambda-mta" to take over email!
Seriously - that 'free.fr' MTA spam block needs fixing if it triggers on proper 7-bit ASCII email that doesn't contain MIME parts (which are usually stuffed with HTML and/or images).
I use Mozilla Thunderbird in "Plain Text" mode. One benefit is there is no possibility to embed hidden malicious links in plain text. Another is small size (some embedded HTML emails are HUGE!).
I like the idea of avoiding any application except the web browser. And I use emails as I use SMS on my smartphone, very small and, when developements have to be given, I just put the link to a wiki page created for this purpose, here it was in the page "sandox". It may be quirky but it is very practical when the developments are important, need to be well formatted, easy to memorize, if they need to allow for group work, etc...
You have noticed that I have eliminated the animation on the Hilbert curve, which reduces the processor load to very little. The load of the "JS setInterval()" used by the "linear watch" being very low I kept this watch.