int ledPins[6] = {12, 11, 10, 9, 8, 7};

void setup() {

for (int i = 0; i < 6 ; i++) {
 pinMode(ledPins[i], OUTPUT);
 
 }
} 

void loop() {
  for (int j = 0; j < 6; j++)  {
    digitalWrite(ledPins[j], HIGH);
    delay(500);
    digitalWrite(ledPins[j], LOW);
    delay(500);


  }

}