const int GPIO_Pins[4]={1,4,9,13};

void setup() {
  // put your setup code here, to run once:
  for(int i=0;i<4;i++){
    pinMode(GPIO_Pins[i], OUTPUT);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  
  for(int j=1;j<=15;j++){
    if(j%2!=0){
      displayBin(j);
      delay(1000);
    }
  }
  for(int k=0;k<4;k++){
    digitalWrite(GPIO_Pins[k],LOW);
  }
  delay(2000);
}


void displayBin(int n){
  int n1=n;
  int r;
  int i=0;
  while(n1!=0){
    r=n1%2;
    if(r==1){
      digitalWrite(GPIO_Pins[i], HIGH);
      i++;
    }
    else{
      digitalWrite(GPIO_Pins[i], LOW);
      i++;
    }
    n1=n1/2;
  }
}