int segPins[] = {0, 1, 2, 3, 4, 5, 6, 7};

void setup() {
  for (int thisPin = 0; thisPin < 8; thisPin++) {
    pinMode(segPins[thisPin], OUTPUT);
  }
}

void loop() {
  for (int thisPin = 0; thisPin < 8; thisPin++) {
    digitalWrite(segPins[thisPin], HIGH);
    delay(500);
  }
  
  for (int thisPin = 0; thisPin < 8; thisPin++) {
    digitalWrite(segPins[thisPin], LOW);
    delay(500);
  }
}