---

const int segPins[] = {6, 7, 8, 9, 10, 11, 12, 13};
const int digitPins[] = {5, 4, 3, 2};

const byte charMasks[4] = {
  0b11101110, // A
  0b00111110, // b
  0b10011100, // C
  0b01111010  // d
};

void setup() {
  for (int i = 0; i < 8; i++) {
    pinMode(segPins[i], OUTPUT);
  }
  
  for (int i = 0; i < 4; i++) {
    pinMode(digitPins[i], OUTPUT);
    digitalWrite(digitPins[i], HIGH);
  }
}

void loop() {
  for (int i = 0; i < 4; i++) {
    for (int d = 0; d < 4; d++) {
      digitalWrite(digitPins[d], HIGH);
    }
    
    digitalWrite(digitPins[i], LOW);
    
    for (int s = 0; s < 8; s++) {
      bool bitVal = bitRead(charMasks[i], 7 - s);
      digitalWrite(segPins[s], bitVal);
    }
    
    delay(2000);
  }
}