Helen example

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Helen, feel free to send me a msg (marzinp@free.fr) if you need more help.

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Ball []myballs;
void setup() {
  size(300, 300);
  myballs=new Ball[4];
  for (int i=0; i<4; i++) {
    myballs[i]=new Ball();
  }
}
void draw() {
  background(255);
  for (Ball myball : myballs) {
    myball.display();
  }
}
void mouseReleased() {
  for (Ball myball : myballs) {
    myball.reactToMouse();
  }
}

class Ball {
  float x, y;
  int diameter=20;
  Ball() {
    x=random(width);
    y=random(height);
  }
  void display() {
    ellipse(x, y, diameter, diameter);
  }
  void reactToMouse() {
    fill(random(255));
    x=random(width);
    y=random(height);
    display();
  }
}