void setup() 
{
pinMode(5,OUTPUT);
pinMode(6,OUTPUT);
pinMode(7,OUTPUT);

}

void loop() 
{
digitalWrite(5,HIGH);
delay(1000);
digitalWrite(5,LOW);
delay(500);

digitalWrite(6,HIGH);
delay(1000);
digitalWrite(6,LOW);
delay(500);

digitalWrite(7,HIGH);
delay(1000);
digitalWrite(7,LOW);
delay(500);

}