​

function setup() {

  createCanvas(600, 600);

  //rectMode(CENTER);

  noFill();

}

​

function draw() {

  background(255);

  fill(0);

  ellipse(0,0,20,20);//haut gauche

  ellipse(width,0,20,20);//haut droit

  ellipse(width,height,20,20);//bas droit

  ellipse(0,height,20,20);//bas gauche

  let r1 = map(mouseX, 0, width, 0, height);

  let r2 = height - r1;

​

  stroke('red');

  line(width-r1/2, height-r1/2, 0, 0);//OK haut gauche

  line(width-r1/2, height-r1/2, width, 0);//haut droit

  line(width-r1/2, height-r1/2, width, height);//ok bas droit

  line(width-r1/2, height-r1/2, 0, height);//bas gauche

​

​

​

  rectMode(CENTER);

  stroke('black');

  fill(255);

  rect(width / 2, height / 2, r2, r2);

​

}