unsigned int cnt1=0, cnt2=2;
void setup() {
  DDRB = 0xFF;
}

void loop() {
  PORTB |= (1<<cnt1);
  PORTB |= (1<<cnt2);
  delay(50);
  PORTB &= ~(1<<cnt1);
  PORTB &= ~(1<<cnt2);
  delay(50);
  cnt1++;
  cnt2++;
  if(cnt1>7)
  cnt1=0;
  if(cnt2>7)
  cnt2=0;
}