#include <Servo.h>

Servo servo1;  // create servo object to control a servo
Servo servo2;  // create servo object to control a servo
Servo servo3;
Servo servo4;

int pos = 0;    // variable to store the servo position

void setup() {
 servo1.attach(9);  
 servo2.attach(10); 
 servo3.attach(11);
 servo4.attach(12);
}

void loop() {
    servo1.write(0);              // tell servo to go to position in variable 'pos'
    delay(150);                       // waits 15ms for the servo to reach the position
    servo2.write(180);              // tell servo to go to position in variable 'pos'
    delay(150);    
     servo3.write(0);              // tell servo to go to position in variable 'pos'
    delay(150);                       // waits 15ms for the servo to reach the position
    servo4.write(180);              // tell servo to go to position in variable 'pos'
    delay(150);    

    servo1.write(180);              // tell servo to go to position in variable 'pos'
    delay(150);                       // waits 15ms for the servo to reach the position
    servo2.write(0);              // tell servo to go to position in variable 'pos'
    delay(150);    
    servo3.write(180);              // tell servo to go to position in variable 'pos'
    delay(150);                       // waits 15ms for the servo to reach the position
    servo4.write(0);              // tell servo to go to position in variable 'pos'
    delay(150);    
}