byte zaeler = 0;

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

void loop() {
  // put your main code here, to run repeatedly:

byte bit0 = zaeler & 0x01;
if (bit0 == 0x01)
{digitalWrite(8, HIGH);}
else
{digitalWrite(8, LOW);}

byte bit1 = zaeler & 0x02;
if (bit1 == 0x02)
{digitalWrite(9, HIGH);}
else
{digitalWrite(9, LOW);}

byte bit2 = zaeler & 0x04;
if (bit2 == 0x04)
{digitalWrite(10, HIGH);}
else
{digitalWrite(10, LOW);}

byte bit3 = zaeler & 0x08;
if (bit3 == 0x08)
{digitalWrite(11, HIGH);}
else
{digitalWrite(11, LOW);}

if (zaeler > 15)
{zaeler = 0;}
else
{zaeler++;}

delay(1000);
}