createCanvas(400, 400);

}

​

function draw() {

  background(220);

​

  mouse = createVector(mouseX, mouseY)

  center = createVector(width / 2, height / 2)

  mouse.sub(center)

  mouse.mult(0.5)

  translate(width / 2, height / 2)

  line(0, 0, mouse.x, mouse.y)

}