int data_pin = 2;
int latch_pin = 4;
int clock_pin = 3;

void setup() {
  // put your setup code here, to run once:
  pinMode(data_pin, OUTPUT);
  pinMode(latch_pin, OUTPUT);
  pinMode(clock_pin, OUTPUT);

  Serial.begin(9600);
  Serial.println("Working !!!");
}

void loop() {
  // put your main code here, to run repeatedly:
  for(int i =0; i < 256; i++){
    digitalWrite(latch_pin, LOW);

    shiftOut(data_pin, clock_pin, MSBFIRST, i);

    digitalWrite(latch_pin, HIGH);
    delay(100);
  }
}