text: let canvas, ctx, ticker = 0;
  
  let drawLine = (x1, y1, x2, y2, color) => {
    //from: top left
    //to:   bottom right
    ctx.beginPath();
    ctx.moveTo(x1, y1);
    ctx.lineTo(x2, y2);
    ctx.strokeStyle = color;
    ctx.stroke();
  };
  
  let setup = () => {
    canvas = document.createElement('canvas')
    canvas.width = 350
    canvas.height = 350
    ctx = canvas.getContext('2d')
    document.body.appendChild(canvas)
  
  }
  
  
  let tick = () => {
    ctx.fillStyle = `white`
    ctx.fillRect(0, 0, canvas.width, canvas.height)
  
    drawLine(ticker % 350, 0, 350, 350, 'red')
    drawLine(0, ticker % 350, 350, 0, 'blue')
  }
  
  setup()
  
  var rAF = function(){
    window.requestAnimationFrame(rAF);
    tick(ticker);
    ticker += 1
  };
  window.requestAnimationFrame(rAF);