void setup() {
  pinMode(25, OUTPUT);
  pinMode(26, OUTPUT);
  pinMode(27, OUTPUT);
}

void setRGB(bool red, bool green, bool blue) {
  digitalWrite(25, red);
  digitalWrite(26, green);
  digitalWrite(27, blue);
}

void loop() {
  setRGB(HIGH, LOW, LOW);   
  delay(1000);

  setRGB(LOW, HIGH, LOW);   
  delay(1000);

  setRGB(LOW, LOW, HIGH);  
  delay(1000);

  setRGB(HIGH, HIGH, LOW); 
  delay(1000);

  setRGB(LOW, HIGH, HIGH);  
  delay(1000);

  setRGB(HIGH, LOW, HIGH);  
  delay(1000);

  setRGB(LOW, LOW, LOW);    
  delay(1000);
}