@OMinazzoli@Quasilocal You can use the wolfram engine ce for personal use for free, or install fir free the full Mathematica on a raspberry pi running raspbian
@probnstat Ok, but beware: the image shows ferrimagnetism, not ferromagnetism, it's similar to anti-ferromagnetism but magnetic momenta of the sublattices don't cancel.
@thebdasgupta@famulare_mike I had much fun doing a demo of the spool problem in class using a diabolo, its friction with the table was perfect. Helped a lot those who couldn't see the theoretical solution was correct.