createCanvas(windowWidth, windowHeight);

  background(0);

}

​

function mouseMoved() {

  if (keyIsPressed && key === 'c') {

    background(0);

  } else {

    fill(mouseY % 255, mouseX % 255, 50);

    //fill(mouseX, 255);

    ellipseMode(CENTER);

    circle(mouseX, mouseY, 24);

  }

​

  if (keyIsPressed === true) {

    fill(0);

  }

}

​