let cx, cy, hw, hh;

​

function setup() {

  rectMode(CENTER);

}

​

function draw() {

  createCanvas(frameCount, frameCount);

  lx = cx - hw;

  rx = cx + hw;

  ty = cy - hh;

  by = cy + hh;

​

  cx = width / 2;

  cy = height / 2;

  hw = width / 20;

  hh = height / 20;

​

​

  background(220);

  stroke(0);

  strokeWeight(5);

​

  line(lx, ty, rx, ty);

  line(lx, by, rx, by);

  line(rx, ty, rx, by);

  line(lx, ty, lx, by);

}