// LED pin matrix
int ledPins[3] = {2, 4, 17};

// Global state variable (1 to 3)
int status = 0;

// Function to turn off all LEDs
void ledsOff() {
  digitalWrite(ledPins[0], LOW);
  digitalWrite(ledPins[1], LOW);
  digitalWrite(ledPins[2], LOW);
}

// Function to show status with IF/ELSE IF
void ledOn() {
  ledsOff();

  if (status == 1) {
    digitalWrite(ledPins[0], HIGH);
  }
  else if (status == 2) {
    digitalWrite(ledPins[1], HIGH);
  }
  else if (status == 3) {
    digitalWrite(ledPins[2], HIGH);
  }
}

// Process control function
void controlProcess_IF() {
  status++;

  if (status > 3) {
    status = 1;
  }

  ledOn();
}

// Initialization
void setup() {
  pinMode(ledPins[0], OUTPUT);
  pinMode(ledPins[1], OUTPUT);
  pinMode(ledPins[2], OUTPUT);
  ledsOff();
}

// Main program
void loop() {
  controlProcess_IF();
  delay(1000); // time delay (1 second)
}