Electronics production ​

// define led according to pin diagram
int led1 = D10;
int led2 = D9;
int led3 = D8;

void setup() {
  // initialize digital pin led as an output
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
}

void loop() {
  digitalWrite(led1, HIGH);   // turn the LED on 
  delay(1000);               // wait for a second
  digitalWrite(led1, LOW);    // turn the LED off
  delay(1000);               // wait for a second
  digitalWrite(led2, HIGH);   // turn the LED on 
  delay(1000);               // wait for a second
  digitalWrite(led2, LOW);    // turn the LED off
  delay(1000);               // wait for a second
  digitalWrite(led3, HIGH);   // turn the LED on 
  delay(1000);               // wait for a second
  digitalWrite(led3, LOW);    // turn the LED off
  delay(1000);               // wait for a second
}