int r = 10;
void setup()
{
background(122,122,122);
size(700,700);  
}

void draw()
{
background(122,122,122);

  
fill(0,255, 0);
ellipse(width/2, height/2, r*5, r*5);

fill(255, 0, 0);
ellipse(width/2, height/2,r*3, r*3);

fill(0, 0, 255);
ellipse(width/2, height/2,r, r);

r++;

}