#define VERDE 13
#define GIALLO 6
#define ROSSO 1

void setup() {
pinMode (VERDE, OUTPUT);
pinMode (GIALLO, OUTPUT);
pinMode (ROSSO, OUTPUT);
}

void loop() {
digitalWrite (ROSSO, LOW);
digitalWrite (GIALLO, LOW);
digitalWrite(VERDE, HIGH);
delay(500);
digitalWrite(ROSSO, LOW);
digitalWrite (GIALLO, HIGH);
digitalWrite(VERDE, LOW);
delay (500);
digitalWrite(ROSSO, HIGH);
digitalWrite (GIALLO, LOW);
digitalWrite (VERDE, LOW);
delay(500);
}