​

function setup() {

  createCanvas(600, 400);

}

​

function draw() {

  if(on) {

  background(0,255, 0);

}  else {

  background(0);

}

  stroke(255);

  strokeWeight(4);

  noFill();

  rectMode(CENTER);

  rect(300, 200, 100, 100);

}

function mousePressed() {

  if (mouseX > 250 && mouseX < 350 && mouseY > 150 && mouseY < 250)

       on = !on;

    }

​

​

  // if (mouseX > 250 && mouseX < 350 && mouseY > 150 && mouseY < 250) {

  //   // between left and right and top and botoom line

  //   if (mouseIsPressed) {

  //   background(0, 255, 0);

  // }

  //   fill(255, 0, 200);

  // }