​

function setup() {

  createCanvas(400, 400);

  background(220);

}

​

function draw() {

  // background(220);

  if(hasMouseMoved){

    circle(mouseX, mouseY, 50);

  }

}

​

function keyTyped() {

  if(key === ' '){

    background(220); // erase canvas by drawing over it

  }

}

​

function mouseMoved() {

  hasMouseMoved = true;

}