x) - Math.sin(rot) * (py - oy) + ox,
    y: Math.sin(rot) * (px - ox) + Math.cos(rot) * (py - oy) + oy
  }

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

  if (this.prevmark) {
    this.engine.ctx.lineWidth = 3;
    this.engine.ctx.setLineDash([16 / this.speed, 8 / this.speed]);

    this.engine.ctx.beginPath();
    this.engine.ctx.moveTo(this.prevmark.