void setup() {
// put your setup code here, to run once:
for(int x=4; x<=13; x++){
pinMode(x, OUTPUT);
}
}
void loop() {
// put your main code here, to run repeatedly:
for(int x=4; x<=13; x++){
digitalWrite(x, HIGH);
delay(300);
digitalWrite(x, LOW);
}
for(int x=13; x>=4; x--){
digitalWrite(x, HIGH);
delay(300);
digitalWrite(x, LOW);
}
}