void setup() {  // program section that runs once
   pinMode(2, OUTPUT);//assign pin 4 and 7 as an output
   pinMode(4, OUTPUT);
}

// the loop function runs over and over again forever

void loop() {  //runs program over and over until stopped
   digitalWrite(2, HIGH); // turn the left LED on
   delay(200); // wait for .2 of a second
   digitalWrite(2, LOW); // turn the LED off
   digitalWrite(4, HIGH);
   delay(200); 
   digitalWrite(4, LOW); // turn the LED off

}