RGBs, photoresistors, and delays
Instead of the two delays of one second, have the program check if the current time is an even or odd number of seconds.

int prPin = A0;

void setup()
{
  pinMode(5,OUTPUT);
  pinMode(6,OUTPUT);
  pinMode(7,OUTPUT);
  pinMode(8,OUTPUT);
  pinMode(9,OUTPUT);
  pinMode(10,OUTPUT);
  pinMode(prPin,INPUT);
  Serial.begin(9600);
}

void loop()
{
    int prVal = analogRead(prPin);
    Serial.write(prVal);
    if(prVal&gt;450)
    {
      if( (millis()/1000)%2 == 0 ) // check if even or odd number of seconds have passes since the program started
      {
        digitalWrite(5,HIGH);
        digitalWrite(6,HIGH);
        digitalWrite(7,HIGH);
        digitalWrite(8,LOW);
        digitalWrite(9,HIGH);
        digitalWrite(10,HIGH);
      } 
      else 
      {
        digitalWrite(5,LOW);
        digitalWrite(6,HIGH);
        digitalWrite(7,HIGH);
        digitalWrite(8,HIGH);
        digitalWrite(9,HIGH);
        digitalWrite(10,HIGH);
      }
    }
    else
    {
      digitalWrite(5,HIGH);
      digitalWrite(6,HIGH);
      digitalWrite(7,LOW);
      digitalWrite(8,HIGH);
      digitalWrite(9,HIGH);
      digitalWrite(10,LOW);
      delay(10);
    }
}