text: let mouseBegin;
  let mouseEnd;
  let size = 5;
  
  function setup() {
    createCanvas(600, 400);
  
    mouseBegin = createVector(0, 0);
    mouseEnd = createVector(0, 0);
  }
  
  function draw() {
    background(0);
  
    if (mouseIsPressed) {
      push();
      stroke(255);
      strokeWeight(2);
      ellipse(mouseBegin.x, mouseBegin.y, size);
      pop();
    }
  }
  
  function mousePressed() {
    mouseBegin.set(mouseX, mouseY);
  }
  
  function mouseReleased() {
    mouseEnd.set(mouseX, mouseY);
  }
  
  function mouseWheel(event) {
    if (event.delta > 0) {
      size -= 3;
    } else {
      size += 3;
    }
  }
  