int latchPin = PB1;
int clockPin = PB0;
int dataPin = PB2;

void setup() {
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  // put your setup code here, to run once:

}

void loop() {
//Random everything
changeLights(random(0,255),random(0,255),random(0,255));
delay(random(100,500));

}

void changeLights(byte b1, byte b2, byte b3){
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, LSBFIRST, b1); 
    shiftOut(dataPin, clockPin, LSBFIRST, b2);
    shiftOut(dataPin, clockPin, LSBFIRST, b3);
    digitalWrite(latchPin, HIGH);
}