int l=15;
int r=2;

void setup() {

  Serial.begin(115200);
  pinMode(l, OUTPUT);
  pinMode(r, OUTPUT);
  Serial.println("Hello, L");
}

void loop() {
  digitalWrite(l, HIGH);
  digitalWrite(r, LOW);
  delay(1000); // this speeds up the simulation
 digitalWrite(r, HIGH);
  digitalWrite(l, LOW);
  delay(1000);
}