int r1 = 50;
int r2 = 50;
int r3 = 50;
void setup(){
size(500,500);  
}
void draw(){ 

r1= r1 + int(random(25));
r2= r2 + int(random(25));
r3= r3 + int(random(25));
fill(255, 0, 0);
ellipse(250,150,r1, r1);

fill(0, 255, 0);
ellipse(250, 250, r2, r2);

fill(0, 0, 255);
ellipse(250, 350, r3, r3);

}