// Pins connected to 74HC595
const int latchPin = 8;
const int clockPin = 12;
const int dataPin = 11;

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

void loop() {
  for (int i = 0; i < 256; i++) { // loop through all 256 possible states
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, i);
    digitalWrite(latchPin, HIGH);
    delay(100);
  }
}