With that solution I can make an increasing separation between ellipses

```
size (1000, 1000);
ellipseMode(CENTER);
noFill();
strokeWeight(1);
for (int j=0,a=0; j<500; j+=1+a) {
ellipse(500,500, j, j);
a=a+1;
}
```

It is my first step, but I need much more ellipses (problem 1) and a small increasing of separation in the center and a big one in the outer part (problem 2), because the center has to be really full and the exterior has to be lighter. So I have done this other version

```
size (1000, 1size (1000, 1000);
ellipseMode(CENTER);
noFill();
strokeWeight(1);
for (int j=0,a=0; j<100; j+=1+a) {
ellipse(500,500, j, j);
a=a+1;
}
for (int k=0, b=0; k<200; k+=1+b){
ellipse(500,500, k,k);
b=b+5/4;
}
for (int l=0, c=0; l<300; l+=1+c){
ellipse(500,500, l,l);
c=c+3/2;
}
for (int m=0, d=0; m<400; m+=1+d){
ellipse(500,500, m,m);
d=d+7/4;
}
for (int n=0, e=0; n<500; n+=1+e){
ellipse(500,500, n,n);
e=e+2;
}
```

So the appearance is similar to the drawing I was looking for

But as you can see it is a blunder, because the growing of the separation is not fluent, as I would prefer, so is there a clean and easy way to get something like this?