createCanvas(400, 400);

  rectMode(CENTER);

}

​

function draw() {

  background(220);

​

  let ball1 = {

    x: mouseX,

    y: mouseY,

    r: 40,

  };

​

  let box1 = {

    x: width / 2,

    y: height / 2,

    r: 40,

  };

  circle(ball1.x, ball1.y, ball1.r);

  square(box1.x, box1.y, box1.r);

  let d = dist(ball1.x, ball1.y, box1.x, box1.y);

  if(d < 100){

    line(ball1.x, ball1.y, box1.x, box1.y);

  }

}

​