In most cases we use these HD44780 LCDs for displaying text messages. But also there are four bytes in LCD RAM that can store custom characters. This is handy when we need special symbol to be displayed. But here is a good example how text LCD can be turned in to graphical display and be used to chow pretty neat graphics.
Program library is written in PicBASIC and runs on PIC16F628A. Library works in similar way as you would write code for graphical display. You can set point coordinates, draw a line or circle. Library takes care of updating custom chars when needed and refresh LCD. As you can see refresh rate is impressive. Playing with refresh and pixel ON times there is also a doubled resolution mode.