eed - Math.abs(this.speed)) / this.maxspeed) + (Math.abs(this.steering * 5));
  a += this.bloodtyres / 128;
  this.engine.ctx.globalAlpha = Math.min(a, .25);
  this.engine.ctx.strokeStyle = `rgba(${this.bloodtyres}, 0, 0, 1)`;

  ...
}
            </code></pre>
          </section>
          <section>
            <iframe width="100%" height="600" data-src="/ch13.html">
            </iframe>
          </section>


          <!-- Performance -->
          <section>
            <h1>Performance</h1>
          <