createCanvas(400, 400);

}

​

function draw() {

  background(0);

  // 0, 100 to 30, 70

  let x = map(mouseX, 0, width,

              (width / 2) - 100, (width / 2) + 100);

  let y = map(mouseY, 0, height,

              (height / 2) - 100, (height / 2) + 100);

  ellipse(x, y, 50, 50);

}