int randNumber;
void setup() {
  Serial.begin(9600);
pinMode(9, OUTPUT);
    pinMode(8, OUTPUT);
    pinMode(10, OUTPUT);
 pinMode(11, OUTPUT);
 randomSeed(analogRead(0));
}

void loop() {
  Serial.println(randNumber);
randNumber = random(8, 12);
 digitalWrite(randNumber, HIGH);
  delay(500);
  digitalWrite(randNumber, LOW);
  delay(500);
}