void setup() {
pinMode(2, OUTPUT); 
pinMode(16, OUTPUT);
pinMode(17, OUTPUT);// put your setup code here, to run once:
}

void loop() {
digitalWrite(2,HIGH);
digitalWrite(16, LOW); 
digitalWrite(17, LOW);// put your main code here, to run repeatedly:
delay(500);
digitalWrite(2,LOW);
digitalWrite(16, HIGH);
digitalWrite(17, LOW);
delay(500);
digitalWrite(2, LOW);
digitalWrite(16, LOW);
digitalWrite(17, HIGH);
delay(500);
  
}