IM LOOKING FOR HELP UNDERSTANDING "two nested for loops"

DOES IT MEAN one loop is included inside the other one?

AND IF SO IS MY CURRENT *****BASIC****** CODE RIGHT?

ANY HELP MUCH APPRECIATED.

CODE:

size(500,500);
noFill();
smooth();
background(0);

for(int x=0; x<500; x=x+60) {       //DOTS
 for(int y=0; y<500; y=y+8) {
   stroke(300*x,300*y/width,128);
   point(x, y);
 }
}

noFill();
for ( int x=8; x< width; x+=10) {    //Outer Spheres L-R
float n= norm( x, 0 ,width ) ;
  float y= radians (n);
  strokeWeight (n*4);
  stroke(355*n,55*y/width,128);
  ellipse ( x,y,-0.3*width,1.6*width);
}

for ( int x=8; x< width; x+=76){   //Inner Rects L-R
  float n= norm( x, 0 ,width ) ;
  float y= radians (n);
  stroke(200*n,6000*y/width,1000);
  y *= width;
  strokeWeight (n*10);
  rect( x,y,-0.1*width,0.75*width);
}