​

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(220);

​

  rect(150, 150, 100, 100);

​

  if (on) {

    fill(0);

  } else {

    fill(255);

  }

  print(on);

​

​

  function mousePressed() {

​

​

    if (mouseX >= 150 && mouseX <= 150 + 100 && mouseY >= 150 && mouseY <= 150 + 100) {

  if (!on) {

    on = false;

  } else {;

    on = true;

  }