The 16×2 character LCD can also be used to display custom characters other than numerals, alphabets & special characters. Refer LCD interfacing with PIC. Some special shapes like hearts, arrows, smileys etc. can easily be displayed on the 5×8 pixel pattern of character LCD. These shapes are first stored at a special location in LCD’s controller and then displayed on the LCD module. This procedure has been explained here by using PIC18F4550.
The special characters are generated by bit-mapping of LCD’s 5×8 bit pixel matrix. Refer Creating custom characters on LCD using 8051 for more details on bitmap generation and storing custom values in custom generator (CG) RAM of LCD’s controller.