let rectH = 100;

let lightSwitch = false;

​

​

function setup() {

  createCanvas(400, 400);

  rectMode(CENTER);

}

​

function draw() {

  background(220);

  noStroke();

  if (!lightSwitch){

    fill(0);

  } else if (lightSwitch) {

    background(0, 255, 0);

    fill(255, 0, 0); // red

    ellipse(width/7,height/2, 100, 100); // place red ellipse on left if lightSwitch is on

    fill(255, 255, 0);

  }

  rect(width/2, height/2, rectW, rectH);

  console.log(mouseX, mouseY);

}

​

function mousePressed(){

  if(mouseX>0 && mouseX<width && mouseY>0 && mouseY<height){ // if mouse is on canvas

    lightSwitch = !lightSwitch; // flip the boolean

  }

}