#define K1 (!(PINB & (1 << PB1)))   // rechts
#define K2 (!(PINB & (1 << PB2)))   // reset
#define K3 (!(PINB & (1 << PB3)))   // links

uint8_t pos = 2;   // LED start op PD2

void setup() {
  DDRD = 0b00111100;      // PD2–5 = LED’s
  PORTD = (1 << pos);     // start LED

  DDRB &= ~0b00001110;    // PB1–3 = knoppen
  PORTB |= 0b00001110;    // pull-ups
}

void loop() {

  if (K1) {               // rechts
    pos++; 
    if (pos > 5) pos = 2;
    PORTD = (1 << pos);
    delay(200);
  }

  if (K3) {               // links
    pos--;
    if (pos < 2) pos = 5;
    PORTD = (1 << pos);
    delay(200);
  }

  if (K2) {               // reset
    pos = 2;
    PORTD = (1 << pos);
    delay(200);
  }
}