#define dataPin 0
#define latchPin 1
#define clockPin 2
#define t 300

const uint16_t pattern[17] = {
  0b0000000000000000,  // 0 blank
  0b1000000000000000,  // 1
  0b0100000000000000,  // 2
  0b0010000000000000,  // 3
  0b0001000000000000,  // 4
  0b0000100000000000,  // 5
  0b0000010000000000,  // 6
  0b0000001000000000,  // 7
  0b0000000100000000,  // 8
  0b0000000010000000,  // 9
  0b0000000001000000,  // 10
  0b0000000000100000,  // 11
  0b0000000000010000,  // 12
  0b0000000000001000,  // 13
  0b0000000000000100,  // 14
  0b0000000000000010,  // 15
  0b0000000000000001   // 16
};

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

void displayDigit(uint16_t d) {
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, LSBFIRST, lowByte(pattern[d]));
  shiftOut(dataPin, clockPin, LSBFIRST, highByte(pattern[d]));
  // shiftOut(dataPin, clockPin, LSBFIRST, lowByte(d));
  // shiftOut(dataPin, clockPin, LSBFIRST, highByte(d));
  digitalWrite(latchPin, HIGH);
}

void loop() {
  for (uint8_t d = 1; d < 17; d++) {
    displayDigit(d);
    delay(t);
  }
  for (uint8_t d = 15; d >= 2; d--) {
    displayDigit(d);
    delay(t);
  }
  //   for (uint16_t d = 0; d <= 0xFFFF; d++) {
  //   displayDigit(d);
  //   delay(t);
  // }
}