Hello, everyone! I am a newbie when it comes to processing, I can understand alittle bit but a lot of times I need explanations.  I really need some help on this question.  

Currently I found a script written by someone which i really like because it takes the time to explain how things work.  I am currently messing around with it and this is what i have so far


float a;

void setup()  
{
 size(800,600);
 stroke(#9d0000);
 frameRate(30);
}

void draw()
{
 
a -= 0.08;
 
background(0);  

 for (int x = -5; x < 25; x++) {
  for (int z = -5; z < 25; z++) {

   int y = int(24 * cos(-0.55 * distance(x,z,0,0) + a));


   float xm = x*17 -8.5;
   float xt = x*17 +8.5;
   float zm = z*17 -8.5;
   float zt = z*17 +8.5;
   
   int halfw = (int)width/2;
   int halfh = (int)height/2;
   
      int isox1 = int(xm - zm + halfw);
   int isoy1 = int((xm + zm) * 0.5 + halfh);
   int isox2 = int(xm - zt + halfw);
   int isoy2 = int((xm + zt) * 1 + halfh);
   int isox3 = int(xt - zt + halfw);
   int isoy3 = int((xt + zt) * 0.5 + halfh);
   int isox4 = int(xt - zm + halfw);
   int isoy4 = int((xt + zm) * 1 + halfh);
   
   fill (#9d0000);
   quad(isox2, isoy2-y, isox3, isoy3-y, isox3, isoy3+40, isox2, isoy2+40);
   fill (#9d0000);
   quad(isox3, isoy3-y, isox4, isoy4-y, isox4, isoy4+40, isox3, isoy3+40);
   
   fill(#9d0000 + y * 0.05);
   quad(isox1, isoy1-y, isox2, isoy2-x, isox3, isoy3-y, isox4, isoy4-x);
  }
 }
}

float distance(float x,float y,float cx,float cy) {
 return sqrt(sq(cx - x) + sq(cy - y));
}

void keyPressed() {
 if (key == CODED) {
   if (keyCode == UP) {
     a -= 0.08 + .1;
   } else if (keyCode == DOWN) {
     a -= 0.08 + .2;
   } else if (keyCode == LEFT) {
     a -= 0.08 + .3;
   } else if (keyCode == RIGHT){
     a -= 0.08 + .5;
 } else {
   a -= 0.08;  
 }
}

currently I have where you push the arrow keys it increases the radius and speed.  Thats good and what I want but i want it so instead of having to push the keys, it does it randomly by itself.
I know about the random function but i cant seem to get it to work.  Any help on how to make this work would be great.  Also if anyone knows how to make it simplier (if thats a word) that would be great as well.  Again the majority of this is not my coding the only thing i did was change some numbers here and there and typed the key functions.  im a newbie. thanks

Also does any one know if there is a code that allows you to open a sketch file within another sketch file?

thanks for the code but i must be doing something wrong cause im getting the same results.  no errors but no difference.  Could you elaborate more as to where to insert this code?  sorry for being a noob