A light runs along eight LEDs on a 74HC595 (pins 11, 12 and 13), on an Arduino Uno

// A running light on a 74HC595: three pins drive eight LEDs.
//
//   74HC595 DS -> pin 11   ST_CP -> pin 12   SH_CP -> pin 13
//   VCC and MR -> 5V   OE and GND -> GND   Q0..Q7 -> 220 ohm -> LEDs -> GND
//
// The byte 0x01 has one bit set. Shifting it left one place each step moves
// the lit LED along: 00000001, 00000010, ... 10000000.

const int LATCH = 12;  // ST_CP
const int CLOCK = 13;  // SH_CP
const int DATA = 11;   // DS

void write595(byte value, int order) {
  digitalWrite(LATCH, LOW);
  shiftOut(DATA, CLOCK, order, value);
  digitalWrite(LATCH, HIGH);
}

void setup() {
  pinMode(LATCH, OUTPUT);
  pinMode(CLOCK, OUTPUT);
  pinMode(DATA, OUTPUT);
  Serial.begin(9600);
  Serial.println("Mokxi Uno: a running light on a 74HC595 (11, 12 and 13)");
}

void loop() {
  byte x = 0x01;
  for (int j = 0; j < 8; j++) {
    write595(x, LSBFIRST);
    x <<= 1;
    delay(100);
  }
  x = 0x80;
  for (int j = 0; j < 8; j++) {
    write595(x, LSBFIRST);
    x >>= 1;
    delay(100);
  }
}