void setup() {
  // put your setup code here, to run once:
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(13, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  for(byte number=0; number<=15; number++){
    for(int bitpos=0; bitpos<4; bitpos++){
      if(bitRead(number, bitpos)) digitalWrite(13-bitpos, HIGH);
      else digitalWrite(13-bitpos, LOW);
    }
    delay(500);
  }
  delay(5000);
}