int ledpins[8]={19,18,5,17,16,4,0,2};
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  for(int i=0;i<8;i++)
  {
    pinMode(ledpins[i],OUTPUT);
  }
}

void loop() {
  for(int i=0;i<8;i++)
  {
    digitalWrite(ledpins[i],HIGH);

  // put your main code here, to run repeatedly:
  delay(1000); // this speeds up the simulation
  }
  for(int i=7;i>=0;i--)
  {
    digitalWrite(ledpins[i], LOW);
    delay(1000);
  }
}