int muxPins[3] = {5,6,7};
int dataPin = 13;

void setup() {
  for(int i = 0; i < 3; i++) {
      pinMode(muxPins[i],OUTPUT);
      digitalWrite(muxPins[i],LOW);
    }
    pinMode(dataPin, OUTPUT);
    digitalWrite(dataPin,HIGH);
    Serial.begin(115200);
  }

void loop() {
  for(int i = 0; i < 8; i++) {
    String bin = String(i,BIN);
    while(bin.length() < 3) {
      bin = "0" + bin;
    }
    
    for(int j = 0; j < 3; j++) {
      digitalWrite(muxPins[j],bin.substring(bin.length()-j-1,bin.length()-j).toInt());
    }
    Serial.println(" ");
     delay(50);
  }
 
  // put your main code here, to run repeatedly:

}