Blinking of two LED at a time programming by ARDUINO

// program for two LEDs on at a time and two LEDs off at same time

//BY-ALOK KUMAR PANDEY

//.................................................................................//

int led1=13, led2=12, led3=11,led4 = 10;

void setup() {

  pinMode(led1, OUTPUT);         // here pin 13(i.e. led1) set as output pin

  pinMode(led2, OUTPUT);         // here pin 12(i.e. led2) set as output pin

  pinMode(led3, OUTPUT);         // here pin 11(i.e. led3) set as output pin

  pinMode(led4, OUTPUT);         // here pin 10(i.e. led4) set as output pin

}

void loop() {

 digitalWrite(led1, HIGH); 

  digitalWrite(led2, HIGH);  

  digitalWrite(led3, LOW);

  digitalWrite(led4, LOW); 

  delay(1000);  

 digitalWrite(led1, LOW); 

  digitalWrite(led2, LOW);  

  digitalWrite(led3, HIGH);

  digitalWrite(led4, HIGH);

  delay(1000); 

}