const int dataPin = 2;  
const int clockPin = 3; 
const int latchPin = 4; 

void setup() {
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
}

void loop() {
  for (int i = 0; i < 8; i++) {
    digitalWrite(latchPin, LOW);
    byte ledState = 1 << (7 - i); 
    shiftOut(dataPin, clockPin, MSBFIRST, ledState);
    digitalWrite(latchPin, HIGH);
    delay(500);
  }
}