It might looks very basic but I'm stuck.
Please, have look to it.

void setup() {
  size(400, 400);
  smooth();
  background(0, 170, 175);
 }

void draw() {
 smooth();
 noFill();
 strokeWeight(10);
 strokeJoin(BEVEL);
 rect(100, 200, 250, 150);
 c1(); //
}

void c1() {
 smooth();
 strokeWeight(5);
 color(100, 80, 20);
 fill(0);
 stroke(250, 100, 100);
 ellipse(250, 200, 80, 80);
 }

 

So I wanted to make a ellipse smooth, but failed.
Could anyone let me know how to amend it?

Many thanks!!!