// include the library code:
 #include <LiquidCrystal.h>

 const int numRows = 2;
 const int numCols = 16;
 
 const int lcdBackLightPin = 12;

 // initialize the library with the numbers of the interface pins
 LiquidCrystal lcd(13, 11, 10, 9, 8, 7);

 void setup() {
   // set up the LCD's number of rows and columns: 
   lcd.begin(numRows, numCols);
   lcd.clear();
   lcd.setCursor(2, 0);
   lcd.print("Hello World!");
   
   pinMode(lcdBackLightPin, OUTPUT);
 }

 void loop() {
   digitalWrite(lcdBackLightPin, HIGH);
   lcd.setCursor(5, 1);
   lcd.print("xISTIx");
   delay(500);
   digitalWrite(lcdBackLightPin, LOW);
   lcd.setCursor(5, 1);
   lcd.print("XistiX");
   delay(500);
 }