ATTiny Knight Rider

This is a little project I built for a friend of mine.
He services mopeds and does alot of custom work for his clients.
You can see some of his work at Meka Scoot Tuning, he is a talented mechanic and body work guy.

Long story short: he requested a small board he wanted to put on one of the mopeds, this is the device I came up with.

See the code in action on Tinkercad

int SERPin = 1;    //OUTPUT
int RCLKPin = 3;   //REFRESH
int SRCLKPin = 4;  //CLOCK
int SPEED = 100;   //millis

#define NumLEDs 16
int LED = NumLEDs - 1;
bool Right = false;

void setup() {
  pinMode(SERPin, OUTPUT);
  pinMode(RCLKPin, OUTPUT);
  pinMode(SRCLKPin, OUTPUT);
}

void loop() {
  for(int i = 0; i < NumLEDs; i++){
    if(i == LED) {
      storedState(1);
    }
    else {
      storedState(0);
    }
  }
  if(Right) {
    LED++;
    if(LED > NumLEDs - 1) {
      Right = false;
      LED = 15;
    }
  } 
  else {
    LED--;
    if(LED < 0) {
      Right = true;
      LED = 0;
    }
  }
  digitalWrite(RCLKPin, HIGH);
  digitalWrite(RCLKPin, LOW);
  delay(SPEED);
}

void storedState(int State) {
  digitalWrite(SERPin, LOW);
  if(State) {
    digitalWrite(SERPin, HIGH);
  }
  digitalWrite(SRCLKPin, HIGH);
  digitalWrite(SRCLKPin, LOW);
  digitalWrite(SERPin, LOW);
}