void setup() {

pinMode(10, OUTPUT);  //blue
pinMode(11, OUTPUT);   //green
pinMode(12, OUTPUT);   //red

}

void loop() {
    //red
  digitalWrite(12, LOW);
  digitalWrite(11, HIGH);
  digitalWrite(10, HIGH);
  delay(1000);

  //green
    digitalWrite(12, HIGH);
  digitalWrite(11, LOW);
  digitalWrite(10, HIGH);
  delay(1000);

  //blue
    digitalWrite(12, HIGH);
  digitalWrite(11, HIGH);
  digitalWrite(10, LOW);
  delay(1000);
 
}