void setup()

 {

pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
blink();

}

void loop()

 {


}
void blink()

{

for(int a=0; a<3;a++ )
{
digitalWrite(4, HIGH);
delay(500);
digitalWrite(4, LOW);
delay(500);

}

digitalWrite(4, LOW);

for(int a=0; a<4;a++ )

{

digitalWrite(3, HIGH);
delay(500);
digitalWrite(3, LOW);
delay(500);

}

digitalWrite(3, LOW);

for(int a=0; a<5;a++ )
{

digitalWrite(2, HIGH);
delay(500);
digitalWrite(2, LOW);
delay(500);

}

digitalWrite(2, LOW);

}