So I wanted to see what free (libre) software had available for graphing calculators:
https://duckduckgo.com/?q=open+source+graphing+calculator
Hint: look for Microsoft in the results.
@freemo I saw that a while ago. It looks pretty cool. Although the software isn't entirely free, it is released under a nonfree license even though the code is available.
Otherwise it looks good.
@MOTT I have the numworks one BTW.