int r_pin = 12, g_pin = 13, b_pin = 14;
void setup() {
  pinMode(r_pin, OUTPUT);
  pinMode(g_pin, OUTPUT);
  pinMode(b_pin, OUTPUT);
}

void loop() {
  color(1, 0, 0);
  delay(500);
  color(0, 1, 0);
  delay(500);
  color(0, 0, 1);
  delay(500);
}

void color(bool r, bool g, bool b) {
  digitalWrite(r_pin, r);
  digitalWrite(g_pin, g);
  digitalWrite(b_pin, b);
}