#define LED_PIN_1 7
#define LED_PIN_2 8
#define LED_PIN_3 12
#define DELAY_TIME 1000
void setup() {
 pinMode(LED_PIN_1, OUTPUT);
 pinMode(LED_PIN_2, OUTPUT);
 pinMode(LED_PIN_3, OUTPUT);
}
void loop() {
 digitalWrite(LED_PIN_1, HIGH);
 digitalWrite(LED_PIN_2, LOW);
 digitalWrite(LED_PIN_3, LOW);
 delay(DELAY_TIME);
 digitalWrite(LED_PIN_1, LOW);
 digitalWrite(LED_PIN_2, HIGH);
 digitalWrite(LED_PIN_3, LOW);
 delay(DELAY_TIME);
 digitalWrite(LED_PIN_1, LOW);
 digitalWrite(LED_PIN_2, LOW);
 digitalWrite(LED_PIN_3, HIGH);
 delay(DELAY_TIME);
}