#include <Servo.h>
Servo a ;
Servo b;
void setup() {
  // put your setup code here, to run once:
a.attach (7);
b.attach (8);
}

void loop() {
  // put your main code here, to run repeatedly:
  
for (int i=0; i<=180;i=i+6) 
{
a.write (i);
b.write (i);
delay(1000);
}
for(int i=180;i>=0;i=i-6)
{a.write (i);
b.write (i);
delay(1000);
}
}