#define DSpin 2
#define LATCHpin 3
#define CLOCKpin 4

uint8_t pattern=0b01010101;


void setup() {
  Serial.begin(9600);
pinMode(DSpin, OUTPUT);
pinMode(LATCHpin, OUTPUT);
pinMode(CLOCKpin, OUTPUT);

digitalWrite(LATCHpin, LOW);

shiftOut(DSpin, CLOCKpin, LSBFIRST, pattern);

digitalWrite(LATCHpin, HIGH);
}

void loop() {
  efekt();
}

int i=0;
bool smer=true;

void efekt(){
  digitalWrite(LATCHpin, LOW);
  shiftOut(DSpin, CLOCKpin, LSBFIRST, pattern);
  digitalWrite(LATCHpin, HIGH);
  delay(200);
  i=(i+1)%1;
  pattern=(smer?pattern<<1:pattern>>1);
  smer=(i==0?!smer:smer);
  
}