// Animates a car with spinning wheels and
// a headlight traveling across screen.
int xval =-35;
int dx = 1;
int angle = 0;


void setup() {
  size(600,150);  
  rectMode(CENTER);
  ellipseMode(CENTER);
}


void draw() {
  background(100);
  carMotion();
}

void carMotion() {
  pushMatrix();
  translate(xval, height/2);
  light();
  carBody();  
  pushMatrix();
  translate(20, 15);
  rotate(radians(angle));
  wheel();
  popMatrix();
  pushMatrix();
  translate(-20, 15);
  rotate(radians(angle));
  wheel();
  popMatrix();

  
  xval += dx;
  angle+= 5;
  if (xval > width+35) xval = 0;
  popMatrix();
}


void carBody() {
  fill(180,180,255);
  rect(0,-25,30,20);
  fill(80,80,255);
  rect(0,0,70,30);
}

void light() {
  noStroke();
  fill(255,255,0);
  if ( (xval% 10) < 5) {
    triangle(35,0,width+35,10,width+35,-10);          
  }
  rect(35,0,10,10);  
  stroke(0);
}
void wheel() {
  fill(0);
  ellipse(0,0,20,20);
  fill(155,100,0);
  rect(0,0,20,6);
}