Understanding Tetris-game code. newbie

Hi All,

Been trying to understand the code in tetris game (in the sticky threads) & i know i have a alot reading /practice to do. it's using advanced methods with arrays and arithmetic and would much appreciate if some one can guide me to good books that's not outdated that would help me take bash understanding further. thanks in advance.

link on the game:

http://www.unix.com/shell-programming-and-scripting/174525-tetris-game-based-shell-script-new-algorithm.html

Thanks in advance.