Car[] cars = new Car[100];


void setup() {
  size(200,400);
  for (int i = 0; i < cars.length; i++){
    cars[i] = new Car(color(i*2),0,i*2,i/20.0);
  }
}

void draw() {
  background(255);
  for (int i = 0; i < cars.length; i++) {
    cars[i].move();
    cars[i].display();
  }
}

class Car {
  
  color c;
  float xpos;
  float ypos;
  float xspeed;
  
  Car(color tempC, float tempXpos, float tempYpos, float tempXspeed) {
    c = tempC;
    xpos = tempXpos;
    ypos = tempYpos;
    xspeed = tempXspeed;
  }
  
  void display() {
    rectMode(CENTER);
    fill(c);
    rect(xpos,ypos,20,10);
  }
  void move() {
    xpos = xpos + xspeed;
    if (xpos>width+11) {
      xpos = 0-11;
    }
  }
}