// Charlieplexing 5 LEDs on 3 pins
int pins[] = {2, 3, 4}; // 3 Arduino pins

// LED mapping: {highPin, lowPin}
int leds[5][2] = {
  {2, 3}, // LED1
  {3, 2}, // LED2
  {3, 4}, // LED3
  {4, 3}, // LED4
  {4, 2}  // LED5
};

void setup() {
  // nothing special
}

void loop() {
  for (int i = 0; i < 5; i++) {
    lightLED(i);
    delay(300);
  }
}

void lightLED(int led) {
  int highPin = leds[led][0];
  int lowPin  = leds[led][1];

  // Set all as INPUT first (high impedance)
  for (int i = 0; i < 3; i++) {
    pinMode(pins[i], INPUT);
  }

  // Drive one HIGH, one LOW
  pinMode(highPin, OUTPUT);
  pinMode(lowPin, OUTPUT);
  digitalWrite(highPin, HIGH);
  digitalWrite(lowPin, LOW);
}