void setup() {
// initialize digital pin LED_BUILTIN as an output.
 pinMode(8, OUTPUT);
 pinMode(10, OUTPUT);
 pinMode(12, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
 digitalWrite(8, HIGH);   // turn the LED on (HIGH is the voltage level)
 delay(3000);  // wait for 3 second
 digitalWrite(8, LOW); // turn the LED off by making the voltage LOW
 delay(100);  // wait for 0.1 second
}