int val[8] = {6,6,6,6,6,6,6,6};
int val_ant[8] = {0,0,0,0,0,0,0,0};

void setup() {
  Serial.begin(115200);
  for(int i=5; i<=12; i++)
    {
      pinMode(i, OUTPUT);
      digitalWrite(i, HIGH);
    }
  randomSeed(analogRead(0));
}

void loop() {
  Serial.print("ON: ");
  for(int i=0; i<8; i++)
    {
     val[i] = random(5,13);
     digitalWrite(val[i], LOW);
     Serial.print(val[i]);
     Serial.print(' ');
    }
  Serial.print("OFF: ");
  for(int i=5; i<=12; i++)
    {
     int count = 0;
     for(int j=0; j<8; j++)
        if (i==val[j]) count++;
     if (count==0) 
      {
        Serial.print(i);
        Serial.print(' ');
        digitalWrite(i, HIGH);
      }
    }
  Serial.println();
  delay(500);
}