Rectangle r;

void setup() {
  size(200, 200);
  background(51);
  framerate(25);

  // Créer le rectangle
  r = new Rectangle(width/2, height/2, 30, 30, color(255, 0, 0), 0.0); 
}  

void draw() {
  background(51);
  
 float alpha = (mouseX + mouseY)/100.0;
 r.pivoter(alpha);
 r.afficher();
}