#define RED 25
#define GREEN 26
#define BLUE 27

void setup() {
  pinMode(RED, OUTPUT);
  pinMode(GREEN, OUTPUT);
  pinMode(BLUE, OUTPUT);
}

void loop() {
  // RED
  digitalWrite(RED, HIGH);
  digitalWrite(GREEN, LOW);
  digitalWrite(BLUE, LOW);
  delay(1000);

  // GREEN
  digitalWrite(RED, LOW);
  digitalWrite(GREEN, HIGH);
  digitalWrite(BLUE, LOW);
  delay(1000);

  // BLUE
  digitalWrite(RED, LOW);
  digitalWrite(GREEN, LOW);
  digitalWrite(BLUE, HIGH);
  delay(1000);

  // OFF
  digitalWrite(RED, LOW);
  digitalWrite(GREEN, LOW);
  digitalWrite(BLUE, LOW);
  delay(1000);
}