int Verm = 12;
  int Amar = 11;
  int Verd = 10;
  int Red = 9;
  int Gre = 8;
  int Sem ;

void setup()
{
    pinMode(Verm, OUTPUT);
    pinMode(Amar, OUTPUT);
    pinMode(Verd, OUTPUT);
    pinMode(Gre, OUTPUT);
    pinMode(Red, OUTPUT);
  Sem = 1;
}

void loop()
{
  if (Sem == 1) {
    digitalWrite (Verm, HIGH);
    digitalWrite (Amar, LOW);
    digitalWrite (Verd, LOW);
    digitalWrite (Red, LOW);
    digitalWrite (Gre, HIGH);
    Sem = Sem + 1;}
  delay(500);
  if (Sem == 2) {
    digitalWrite (Verm, LOW);
    digitalWrite (Amar, HIGH);
    digitalWrite (Verd, LOW);
    digitalWrite (Red, HIGH);
    digitalWrite (Gre, LOW);
    Sem = Sem + 1;}
  delay(200);
  if (Sem == 3) {
    digitalWrite (Verm, LOW);
    digitalWrite (Amar, LOW);
    digitalWrite (Verd, HIGH);
    digitalWrite (Red, HIGH);
    digitalWrite (Gre, LOW);
    Sem = Sem + 1;}
  delay(300);
  if (Sem == 4) {
    Sem = 1;
  }
}