int red = 13;
int grn = 10;
int blu = 7;
int ylw = 4;

void runlds(const int lds[], int qnt, int clk) {
  for (int i = 0; i < qnt; i++) {
    pinMode(lds[i], OUTPUT);
    digitalWrite(lds[i], 1);
    delay(clk);
  }
  for (int i = 0; i < qnt; i++) {
    digitalWrite(lds[i], 0);
  }
}
int lds[] = {red, grn, blu, ylw};

void setup() { 
}

void loop() {
  runlds(lds, 4, 500);
}