Hello,
That you for your support.

I am a beginner in PHP.
I forgot to say you, I use Tinyportal Responsive Beta!
I tested the second code again, and it crashed the portal.
The third code work (surrounded in green), but it don't do that I want...
In red, this is the list that I would want on a page.
My request:
Category 1:
Artilce 1
Article 2
Article 3
etc
Category 2:
Artilce 4
Article 6
Article 9
etc
Category 3:
Artilce 5
Article 8
etc
I hope it's more clear...