void setup() {
  // put your setup code here, to run once:
pinMode(2, OUTPUT);
pinMode(4, OUTPUT);
pinMode(6, OUTPUT);
pinMode(8, OUTPUT);
pinMode(10, OUTPUT);
}

void loop() {
  // put your setup code here, to run once:
digitalWrite(2, HIGH);
delay(250);
digitalWrite(2, LOW);
delay(250);
digitalWrite(4, HIGH);
delay(250);
digitalWrite(4, LOW);
delay(250);
digitalWrite(6, HIGH);
delay(250);
digitalWrite(6, LOW);
delay(250);
digitalWrite(8, HIGH);
delay(250);
digitalWrite(8, LOW);
delay(250);
digitalWrite(10, HIGH);
delay(250);
digitalWrite(10, LOW);
delay(250);
digitalWrite(8, HIGH);
delay(250);
digitalWrite(8, LOW);
delay(250);
digitalWrite(6, HIGH);
delay(250);
digitalWrite(6, LOW);
delay(250);
digitalWrite(4, HIGH);
delay(250);
digitalWrite(4, LOW);
delay(250);
}