int latchPin = 5;      
int clockPin = 6;      
int dataPin = 4;       

byte leds = 0;         // Variable to hold the pattern of which LEDs are currently turned on or off


void setup() 
{
  // Set all the pins of 74HC595 as OUTPUT
  pinMode(latchPin, OUTPUT);
  pinMode(dataPin, OUTPUT);  
  pinMode(clockPin, OUTPUT);
}


void loop() 
{
  leds = 0;
  updateShiftRegisterR();
  delay(100);
  for (int i = 0; i < 8; i++){
  bitSet(leds, i);
  updateShiftRegisterR();
  delay(100);

}

  leds = 0;
  updateShiftRegisterL();
  delay(100);
  for (int i = 0; i < 8; i++){
  bitSet(leds, i);
  updateShiftRegisterL();
  delay(100);

}

}


}

// https://lastminuteengineers.com/74hc595-shift-register-arduino-tutorial