// Define LED pins
#define ARRAY_LEN(x) (sizeof(x) / sizeof((x)[0]))

//int LED[]  {25, 26, 27, 14, 19, 18, 5, 17};   // anti clock
//int LED[]  {17, 5,18,19,14,27,26,25};         // clock
int LED[]  {17, 25, 5, 26, 18, 27, 19, 14};     // zigzag



void setup() {
  
  // Set pins as outputs
  for (int i = 0; i < ARRAY_LEN(LED); i++)
  {
    pinMode(LED[i], OUTPUT);
    digitalWrite(LED[i], LOW);
    if (i == 0) digitalWrite(LED[i], HIGH);
  }
}

void loop() {

  for (int i = 0; i < ARRAY_LEN(LED); i++)
  {
    if (digitalRead(LED[i]) == HIGH)
    {
      digitalWrite(LED[i], LOW);
      if (i == ARRAY_LEN(LED)-1) digitalWrite(LED[0], HIGH);
      else digitalWrite(LED[i+1], HIGH);
      break;
    }
  }
  delay(500);
}