I'm starting to experiment with an LCD screen. I just tried the Hello world project, but I came across a problem. My 2x16 LCD displays rectangles over the first line (picture below). Instead of hooking it up to a potentiometer, I put the LCD pin labeled "Vo" in the "GND" port on the arduino. The LCD screen is a 3.3 volt, so I have it plugged into 3.3V on the arduino.