Twinkle Code

long randNumber1,randNumber2;
int var;
int startLED1 = 1;
int endLED1 = 11;
int startLED2 = 11;
int endLED2 = 21;

int delayTime = 50;

void setup(){
    randomSeed(analogRead(0));
    var = startLED1;
    while(var < endLED1){
        pinMode(var, OUTPUT);
    var++;
    }
    var = startLED2;
    while(var < endLED2){
        pinMode(var, OUTPUT);
    var++;
    }
}

void loop(){
    randNumber1 = random(startLED1,endLED1);
    randNumber2 = random(startLED2,endLED2);
    digitalWrite(randNumber1, !digitalRead(randNumber1));
    digitalWrite(randNumber2, !digitalRead(randNumber2));
    delay(delayTime);
}