#include <Servo.h>

Servo myservo;  // create servo object

void setup() {
  myservo.attach(10);  // attaches the servo on pin 10
  myservo.write(50);   // moves the servo to 50 degrees
}

void loop() {
  myservo.write(50);   // moves the servo to 50 degrees
  delay(1000);         // pauses for 1 second
  myservo.write(0);   // moves the servo to 0 degrees
  delay(1000);         // pauses for 1 second
  myservo.write(50);   // moves the servo to 50 degrees
  delay(1000);         // pauses for 1 second
  myservo.write(100);   // moves the servo to 100 degrees
  delay(1000);         // pauses for 1 second
}