int r = 25;
int g = 26;
int b = 27;
void setup() {
pinMode(r, OUTPUT);
pinMode(g, OUTPUT);
pinMode(b, OUTPUT);
}
void loop() {
 green();
 delay(1500);
 yellow();
 delay(1000);
 red();
 delay(1500);
}

void red() {
  digitalWrite(r,1);
  digitalWrite(g,0);
  digitalWrite(b,1);
  delay(1000);
}
void green() {
  digitalWrite(r,0);
  digitalWrite(g,1);
  digitalWrite(b,1);
  delay(1000);
}
void yellow() {
  digitalWrite(r,0);
  digitalWrite(g,0);
  digitalWrite(b,1);
  delay(1000);
}