const int GPIO_Pin=0;
const int GPIO_Pin1=1;
const int GPIO_Pin2=2;
const int GPIO_Pin3=3;

void setup() {
  // put your setup code here, to run once:
  Serial1.begin(115200);
  Serial1.println("Hello, Raspberry Pi Pico!");
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(GPIO_Pin, OUTPUT);
  pinMode(GPIO_Pin1, OUTPUT);
   pinMode(GPIO_Pin2, OUTPUT);
   pinMode(GPIO_Pin3, OUTPUT);
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(100);
  digitalWrite(LED_BUILTIN, LOW);
  delay(100);

  digitalWrite(GPIO_Pin, HIGH);
     delay(500);
   digitalWrite(GPIO_Pin1, HIGH);
      delay(500);
   digitalWrite(GPIO_Pin2, HIGH);
      delay(500);
   digitalWrite(GPIO_Pin3, HIGH);
   delay(500);
  digitalWrite(GPIO_Pin, LOW); 
   
  digitalWrite(GPIO_Pin1, LOW);
    
  digitalWrite(GPIO_Pin2, LOW);
    
  digitalWrite(GPIO_Pin3, LOW);
  delay(500);

  // put your main code here, to run repeatedly:
  delay(1); // this speeds up the simulation
}