const int RED_LED_PIN = 11;
const int GRN_LED_PIN = 10;
const int BLU_LED_PIN =  9;

void setup() 
{
  Serial.begin(115200);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(GRN_LED_PIN, OUTPUT);
  pinMode(BLU_LED_PIN, OUTPUT);
}

void loop() 
{
  Serial.println("Red");
  digitalWrite(RED_LED_PIN, HIGH);
  digitalWrite(GRN_LED_PIN, LOW);
  digitalWrite(BLU_LED_PIN, LOW);
  delay(2000);

  Serial.println("Green");
  digitalWrite(RED_LED_PIN, LOW);
  digitalWrite(GRN_LED_PIN, HIGH);
  digitalWrite(BLU_LED_PIN, LOW);
  delay(2000);

  Serial.println("Blue");
  digitalWrite(RED_LED_PIN, LOW);
  digitalWrite(GRN_LED_PIN, LOW);
  digitalWrite(BLU_LED_PIN, HIGH);
  delay(2000);   
}