​

function setup() {

  createCanvas(240, 120)

  x = width / 2

}

​

function draw() {

  background(204)

  if (mouseX < x) {

    x -= .5

    offset = 10

  } else if (mouseX > x) {

    x += .5

    offset = -10

  }

  line(x, 0, x, height)

  line(mouseX, mouseY, mouseX+offset, mouseY-10)

  line(mouseX, mouseY, mouseX+offset, mouseY+10)

  line(mouseX, mouseY, mouseX+offset*3, mouseY)

}