In the last few days/week, I have been trying to read some tutorials, but as you all probably know, the wiki is down.
However, I found the following link:
http://davidb.github.io/sandbox_wiki_jme/jme3.html
That is a normal and working wiki (?).
Is this a different, new website, or an old (maybe outdated or broken) link?
Don’t answer stuff like “you can use the SDK” please.
It is an experiment but it’s been made with the backup of the wiki. So yes it should be accurate. If you find any inconsistencies please report them.
And btw this is where the wiki link in the menu above will bring you.
@nehon is it also possible to fix the menu links for Math for dummies and Scenegraph for dummies? Just to remove some broken links, while we wait for the definitive solution 
here are the links @david_bernard_31 posted Math for dummies - Scenegraph for dummies
Done 
