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

void loop() 
{
digitalWrite(7, HIGH);  
digitalWrite(6, LOW);
digitalWrite(5, LOW);
delay(6000);
digitalWrite(7, LOW);  
digitalWrite(6, HIGH);
digitalWrite(5, LOW);
delay(6000);
digitalWrite(7, LOW);  
digitalWrite(6, LOW);
digitalWrite(5, HIGH);
delay(6000);


}