// this means comment, can put for people to read and not distrupt the process
// integer variable
int RED_LED = 18;
// I have a variable named RED_LED
// & its value is 18
// Later on, i can use RED_LED for number 18 

void setup() {
  // put your setup code here, to run once:
  pinMode(RED_LED, OUTPUT);}

void loop() {
  // put your main code here, to run repeatedly:
 digitalWrite(RED_LED, HIGH);
 delay(100);
 digitalWrite(RED_LED, LOW);
 delay(100);}