void setup() {
  size(200, 200);
  smooth();
  background(255);
  stroke(0, 50);
  fill(70, 240, 97, 10);
}

void draw() {
  drawCircles();
}

void drawCircles() {
  int x = mouseX;
  int y = mouseY;
  ellipse(x, y, 50, 50);
  ellipse(x, y, 40, 40);
  ellipse(x, y, 30, 30);
}