While this may not exactly belong in this section it deserves to be shown for what can come out of true open source projects offered back to all.
Not just about the Tech but the Man and his thinking behind the project and then what he has made out of it and how so much more has been made by others. And no I am not meaning just $$$ either.
Tom Sanladerer has just put up a great Video interview with Adrian Bowyer which is well worth a watch.
https://reprap.org/wiki/RepRaphttps://youtu.be/VV0Tjwq7Uc0