void setup() {
  pinMode(0, INPUT);   //THE BUTTON
  pinMode(3, OUTPUT);  //RED PIN
  pinMode(2, OUTPUT);  //GREEN PIN
  pinMode(1, OUTPUT);  //BLUE PIN
}
//when the button is pressed the blue and green lights turn on
//this causes a yellow color.
//please note, there are lots of resistors.
//these are built in on our arduinos.
void loop() {

  if (digitalRead(0) == HIGH) {
    digitalWrite(1, HIGH);
    digitalWrite(2, HIGH);
  } else {
    digitalWrite(2, LOW);
    digitalWrite(1, LOW);
  }
}