// C++ code
//
void setup()
{
  pinMode(2, OUTPUT); //r1
  pinMode(3, OUTPUT); //y1
  pinMode(4, OUTPUT); //g1
  pinMode(6, OUTPUT); //r2
  pinMode(7, OUTPUT); //y2
  pinMode(8, OUTPUT); //g2
  pinMode(16, OUTPUT); //r3
  pinMode(17, OUTPUT); //y3
  pinMode(18, OUTPUT); //g3
  pinMode(26, OUTPUT); //r4
  pinMode(27, OUTPUT); //y4
  pinMode(28, OUTPUT); //g4
}

void loop()
{
  //all yellow
  digitalWrite(3, HIGH);
  digitalWrite(17, HIGH);
  digitalWrite(7, HIGH);
  digitalWrite(27, HIGH);
  delay(2000);
  digitalWrite(3, LOW);
  digitalWrite(17, LOW);
  digitalWrite(7, LOW);
  digitalWrite(27, LOW);

//GREEN1
  digitalWrite(4, HIGH);
  digitalWrite(6, HIGH);
  digitalWrite(16, HIGH);
  digitalWrite(26, HIGH);
  delay(2000);
  digitalWrite(4, LOW);
  digitalWrite(6, LOW);
  digitalWrite(16, LOW);
  digitalWrite(26, LOW);

//YELLOW1,2
  digitalWrite(3, HIGH);
  digitalWrite(7, HIGH);
  digitalWrite(16, HIGH);
  digitalWrite(26, HIGH);
  delay(2000);
  digitalWrite(3, LOW);
  digitalWrite(7, LOW);
  digitalWrite(16, LOW);
  digitalWrite(26, LOW);

//GREEN2
  digitalWrite(2, HIGH);
  digitalWrite(8, HIGH);
  digitalWrite(16, HIGH);
  digitalWrite(26, HIGH);
  delay(2000);
  digitalWrite(2, LOW);
  digitalWrite(8, LOW);
  digitalWrite(16, LOW);
  digitalWrite(26, LOW);

//YELLOW2,3
  digitalWrite(2, HIGH);
  digitalWrite(7, HIGH);
  digitalWrite(17, HIGH);
  digitalWrite(26, HIGH);
  delay(2000);
  digitalWrite(2, LOW);
  digitalWrite(7, LOW);
  digitalWrite(17, LOW);
  digitalWrite(26, LOW);

//GREEN3
  digitalWrite(2, HIGH);
  digitalWrite(7, HIGH);
  digitalWrite(18, HIGH);
  digitalWrite(26, HIGH);
  delay(2000);
  digitalWrite(2, LOW);
  digitalWrite(7, LOW);
  digitalWrite(18, LOW);
  digitalWrite(26, LOW);

//YELLOW3,4
  digitalWrite(2, HIGH);
  digitalWrite(6, HIGH);
  digitalWrite(17, HIGH);
  digitalWrite(27, HIGH);
  delay(2000);
  digitalWrite(2, LOW);
  digitalWrite(6, LOW);
  digitalWrite(17, LOW);
  digitalWrite(27, LOW);

//GREEN4
  digitalWrite(2, HIGH);
  digitalWrite(6, HIGH);
  digitalWrite(16, HIGH);
  digitalWrite(28, HIGH);
  delay(2000);
  digitalWrite(2, LOW);
  digitalWrite(6, LOW);
  digitalWrite(16, LOW);
  digitalWrite(28, LOW);
}