void setup() {
  // put your setup code here, to run once:
pinMode(13, OUTPUT);
pinMode(11, OUTPUT);
pinMode(10, OUTPUT);
pinMode(9, OUTPUT);
pinMode(8, OUTPUT);
pinMode(7, OUTPUT);
pinMode(6, OUTPUT);
pinMode(5, OUTPUT);
pinMode(4, OUTPUT);
}

void loop() {
  // Display 0
digitalWrite(11, HIGH);
digitalWrite(10, HIGH);
digitalWrite(9, HIGH);
digitalWrite(8, HIGH);
digitalWrite(7, HIGH);
digitalWrite(6, HIGH);
digitalWrite(5, LOW);
digitalWrite(4, HIGH);

delay(500);

// Display 1
digitalWrite(11, LOW);
digitalWrite(10, HIGH);
digitalWrite(9, HIGH);
digitalWrite(8, LOW);
digitalWrite(7, LOW);
digitalWrite(6, LOW);
digitalWrite(5, LOW);
digitalWrite(4, HIGH);

delay(500);

// Display 2
digitalWrite(11, HIGH);
digitalWrite(10, HIGH);
digitalWrite(9, LOW);
digitalWrite(8, HIGH);
digitalWrite(7, HIGH);
digitalWrite(6, LOW);
digitalWrite(5, HIGH);
digitalWrite(4, HIGH);

delay(500);

// Display 3
digitalWrite(11, HIGH);
digitalWrite(10, HIGH);
digitalWrite(9, HIGH);
digitalWrite(8, HIGH);
digitalWrite(7, LOW);
digitalWrite(6, LOW);
digitalWrite(5, HIGH);
digitalWrite(4, HIGH);

delay(500);

digitalWrite(13, HIGH);
delay(500);
digitalWrite(13, LOW);
delay(500);

}