int GREEN = 12;
int YELLOW = 11;
int RED = 10;

void setup()
{
  pinMode(GREEN, OUTPUT);
  pinMode(YELLOW, OUTPUT);
  pinMode(RED, OUTPUT);

  pinMode(2, OUTPUT);  
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
}

void count9()
{
   // write '8'
  digitalWrite(2, 0);
  digitalWrite(3, 0);
  digitalWrite(4, 0);
  digitalWrite(5, 0);
  digitalWrite(6, 0);
  digitalWrite(7, 0);
  digitalWrite(8, 0);
  delay(1000);
  // write '7'
  digitalWrite(2, 0);
  digitalWrite(3, 0);
  digitalWrite(4, 0);
  digitalWrite(5, 1);
  digitalWrite(6, 1);
  digitalWrite(7, 1);
  digitalWrite(8, 1);
  delay(1000);
  // write '6'
  digitalWrite(2, 0);
  digitalWrite(3, 1);
  digitalWrite(4, 0);
  digitalWrite(5, 0);
  digitalWrite(6, 0);
  digitalWrite(7, 0);
  digitalWrite(8, 0);
  delay(1000);
  // write '5'
  digitalWrite(2, 0);
  digitalWrite(3, 1);
  digitalWrite(4, 0);
  digitalWrite(5, 0);
  digitalWrite(6, 1);
  digitalWrite(7, 0);
  digitalWrite(8, 0);
  delay(1000);
  // write '4'
  digitalWrite(2, 1);
  digitalWrite(3, 0);
  digitalWrite(4, 0);
  digitalWrite(5, 1);
  digitalWrite(6, 1);
  digitalWrite(7, 0);
  digitalWrite(8, 0);
  delay(1000);
  // write '3'
  digitalWrite(2, 0);
  digitalWrite(3, 0);
  digitalWrite(4, 0);
  digitalWrite(5, 0);
  digitalWrite(6, 1);
  digitalWrite(7, 1);
  digitalWrite(8, 0);
  delay(1000);
  // write '2'
  digitalWrite(2, 0);
  digitalWrite(3, 0);
  digitalWrite(4, 1);
  digitalWrite(5, 0);
  digitalWrite(6, 0);
  digitalWrite(7, 1);
  digitalWrite(8, 0);
  delay(1000);
  // write '1'
  digitalWrite(2, 1);
  digitalWrite(3, 0);
  digitalWrite(4, 0);
  digitalWrite(5, 1);
  digitalWrite(6, 1);
  digitalWrite(7, 1);
  digitalWrite(8, 1);
  delay(1000);
  // write '0'
  digitalWrite(2, 0);
  digitalWrite(3, 0);
  digitalWrite(4, 0);
  digitalWrite(5, 0);
  digitalWrite(6, 0);
  digitalWrite(7, 0);
  digitalWrite(8, 1);
  delay(1000);
}

void count2()
{
  // write '1'
  digitalWrite(2, 1);
  digitalWrite(3, 0);
  digitalWrite(4, 0);
  digitalWrite(5, 1);
  digitalWrite(6, 1);
  digitalWrite(7, 1);
  digitalWrite(8, 1);
  delay(1000);
  // write '0'
  digitalWrite(2, 0);
  digitalWrite(3, 0);
  digitalWrite(4, 0);
  digitalWrite(5, 0);
  digitalWrite(6, 0);
  digitalWrite(7, 0);
  digitalWrite(8, 1);
  delay(1000);
}

void loop()
{
  //Green LED
  digitalWrite(GREEN, HIGH);
  digitalWrite(YELLOW, LOW);
  digitalWrite(RED, LOW);
  count9();
  
  //Yellow LED
  digitalWrite(GREEN, LOW);
  digitalWrite(YELLOW, HIGH);
  digitalWrite(RED, LOW);
  count2();
  
  //Red LED
  digitalWrite(GREEN, LOW);
  digitalWrite(YELLOW, LOW);
  digitalWrite(RED, HIGH);
  count9();

  //Yellow LED
  digitalWrite(GREEN, LOW);
  digitalWrite(YELLOW, HIGH);
  digitalWrite(RED, LOW);
  count2();
}