void setup()
{
  size(800, 800);
}

float speed = 1;
boolean forward = true;

void draw()
{
  noStroke();

  // Sky
  fill(80 + 90 * speed, 130 + 90 * speed, 200 + 90 * speed);
  rect(0, 0, 800, 400);

  // Sun
  fill(253, 184, 19);
  ellipse(400, 350 + 100 - 300 * speed, 100, 100);

  // Grass
  fill(30 + 100 * speed, 160 + 130 * speed, 0);
  rect(0, 400, 800, 800);

  // Street
  fill(0, 0, 0);
  triangle(200, 800, 400, 400, 600, 800);

  // Car
  if (forward)
  {
    for (float i = 0; i < 15; i = i + 1)
    {
      car(60 * speed + i * speed + 400, 400 * speed - i * speed + 400, false);
    }
    speed = speed - 0.003;
    if (speed <= 0)
    {
      forward = false;
    }
  }
  else
  {
    for (float i = 0; i < 15; i = i + 1)
    {
      car(-60 * speed - i * speed + 400, 400 * speed - i * speed + 400, true);
    }
    speed = speed + 0.003;
    if (speed >= 1)
    {
      speed = 1;
    }
  }
}

void car(float x, float y, boolean front)
{
  float yScale = (y - 400) / 400;
  float yScale2 = (y - 400 - 100 * yScale) / 400;

  if (front)
  {
    //P1 x - 80 * yScale, y
    //P2 x, y
    //P3 x - 80 * yScale + 20 * yScale2, y - 100 * yScale2
    //P4 x - 80 * yScale + 20 * yScale2 + 80 * yScale2, y - 100 * yScale2

    fill(255, 0, 0);
    triangle(x - 80 * yScale, y, x, y, x - 80 * yScale2 + 20 * yScale2, y - 100 * yScale2);
    triangle(x, y, x - 80 * yScale2 + 20 * yScale2, y - 100 * yScale2, x - 80 * yScale2 + 20 * yScale2 + 80 * yScale2, y - 100 * yScale2);
  }
  else
  {
    //P1 x, y
    //P2 x + 80 * yScale, y
    //P3 x - 20 * yScale2, y - 100 * yScale2
    //P4 x - 20 * yScale2 + 80 * yScale2, y - 100 * yScale2

    fill(255, 0, 0);
    triangle(x, y, x + 80 * yScale, y, x - 20 * yScale2, y - 100 * yScale2);
    triangle(x + 80 * yScale, y, x - 20 * yScale2, y - 100 * yScale2, x - 20 * yScale2 + 80 * yScale2, y - 100 * yScale2);
  }
}