void setup() { 
pinMode(7, OUTPUT); //GREEN LED
pinMode(8, OUTPUT); //ORANGE LED
pinMode(9, OUTPUT); //RED LED
Serial.begin(9600);
}

void loop() {

for(int green=10; green>=1; green--){
digitalWrite(7, HIGH);
digitalWrite(8, LOW);
digitalWrite(9, LOW);
Serial.print(" GO ");
Serial.println(green);
delay(1000);
}
for(int orange=10; orange>=1; orange--){
digitalWrite(7, LOW);
digitalWrite(8, HIGH);
digitalWrite(9, LOW);
Serial.print(" CAUTION ");
Serial.println(orange);
delay(1000);
}
for(int red=10; red>=1; red--){
digitalWrite(7, LOW);
digitalWrite(8, LOW);
digitalWrite(9, HIGH);
Serial.print(" STOP ");
Serial.println(red);
delay(1000);
}

}