Yeah sorry forgot it there!!!
Anyway I tried do that stuff but I get this error:
Cannot make a static reference to the non-static method random(float, float) from the type PApplet
I see that I have 3 random() functions and when I comment that the error goes to the next one!
If I comment out all random function the class works! But I need that random function 
Well, Im doing a Matrix class, maybe you already have one to share with static method