void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(12,OUTPUT);
  pinMode(26,OUTPUT);
  pinMode(33,OUTPUT);
  pinMode(15,OUTPUT);
}

void loop() {
  digitalWrite(12,HIGH);
  digitalWrite(26,HIGH);
  digitalWrite(33,HIGH);
  digitalWrite(15,HIGH);
  delay(50);
  digitalWrite(12,LOW);
  digitalWrite(15,LOW);
  digitalWrite(33,LOW);
  digitalWrite(26,LOW);
  delay(50);
}