int pin[] = {23,22,21,19,18,5,17,16,4};
void setup() {
  for(int i = 0;i<9;i++){
    pinMode(pin[i], OUTPUT);
  }
}
void loop() {
  for(int i = 0;i<4;i++){   //USED NESTED LOOP
    delay(1000);
    for(int n = 0; n<9;n++){     //TO SHUT OFF THE LEDs AFTER EACH ALPHABET
      digitalWrite(pin[n], LOW);
    }
    delay(1000);
    for (int j = 0;j<9;j++){
      //FOR "A"
      if(i == 0){
        if(pin[j]==16){
          continue;
        }
      }
      //FOR "B" ALL THE LED SHOULD BE LIGHT UP
      //FOR "C"
      else if(i == 2){
        if((pin[j]==18)||(pin[j] ==5)){
          continue;
        }
      }
      //FOR "D"
      else if(i==3){
        if(pin[j]==18){
          continue;
        }
      }
      digitalWrite(pin[j], HIGH);
    }
  delay(1000);
  }
}