int ledPins[] = {22,23,24,25,26,27,28,29};

void setup() {
  // put your setup code here, to run once:
  for(int i = 0; i<8; i++){
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  for(int i = 7; i > -1; i--){
    digitalWrite(ledPins[i], HIGH);
    delay(500);
    digitalWrite(ledPins[i], LOW);
  }

  for(int i = 0; i < 8; i++){
    digitalWrite(ledPins[i], HIGH);
    delay(500);
    digitalWrite(ledPins[i], LOW);
  }
}