#include <Servo.h>
Servo servo;

void setup() {
  servo.attach(4);
  servo.write(0);
  delay(500);
  // put your setup code here, to run once:
}

void loop() {
  servo.write(180);
  delay(500);
  servo.write(90);

  // put your main code here, to run repeatedly:
  delay(100);
  servo.write(0);
  delay(100); // this speeds up the simulation
}