int merah = 13;
int kuning =11;
int hijau = 9;
int button = 3;

int ButtonState = 0;
int x = 0;

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode (merah, OUTPUT);
pinMode (kuning, OUTPUT);
pinMode (hijau, OUTPUT);
pinMode (button, INPUT_PULLUP);
}

void loop() {
  // put your main code here, to run repeatedly:
ButtonState = digitalRead (button);
delay (500);

if (ButtonState==LOW) {
  x++ ;
}
switch (x) {
  case 1:
  digitalWrite (merah,HIGH);
  digitalWrite (kuning, LOW);
  digitalWrite (hijau, LOW);
  break;
  case 2:
  digitalWrite (merah,LOW);
  digitalWrite (kuning, HIGH);
  digitalWrite(hijau, LOW);
  break;
  case 3:
  digitalWrite(merah, LOW);
  digitalWrite(kuning, LOW);
  digitalWrite (hijau, HIGH);
  break;
  case 4:
  digitalWrite (merah, HIGH);
  digitalWrite (kuning, HIGH);
  digitalWrite (hijau, HIGH);
  break;
  default:
  if (x>=5) {
    x =0;
  }
  break;
}
}