void setup() {
  size(300,300);
  background(0);
  noStroke();
  smooth();
}

void draw () {
  if (keyPressed == true) {
    switch (key) {
    case '1':
      fill(255,5);
      ellipse(150,150,50,50);
      break;
    case '2':
      fill(255,5);
      ellipse(150,150,100,100);
      break;
    case '3':
      fill(255,5);
      ellipse(150,150,200,200);
      break;
    case '4':
      fill(255,5);
      ellipse(150,150,300,300);
      break;
    case '0':
      fill(0,10);
      ellipse(150,150,350,350);
      break;
    }
  }

}