let y = 200;

let extraCanvas;

​

function setup() {

  createCanvas(400, 400);

  extraCanvas = createGraphics(400, 400);

  extraCanvas.clear();

  background(0);

}

​

function draw() {

  // No trails!

  background(0);

  x += random(-5, 5);

  y += random(-5, 5);

  // trails

  //if (mouseIsPressed) {

    extraCanvas.fill(255, 150);

    extraCanvas.noStroke();

    let starX = random(width);

    let starY = random(height);

    extraCanvas.ellipse(starX, starY, 10, 10);

    //extraCanvas.ellipse(mouseX, mouseY, 60, 60);

  //}

  image(extraCanvas, 0, 0);

  fill(255, 0, 0);

  stroke(255);

  rectMode(CENTER);

  rect(x, y, 20, 20);

​

}