This chapter covers the entire explanation of how the Memory Puzzle program works. Read over the chapter and the source code again to understand it better. Many of the other game programs in this book make use of the same programming concepts (like nested
for loops, syntactic sugar, and different coordinate systems in the same program) so they won’t be explained again to keep this book short.
One idea to try out to understand how the code works is to intentionally break it by commenting out random lines. Doing this to some of the lines will probably cause a syntactic error that will prevent the script from running at all. But commenting out other lines will result in weird bugs and other cool effects. Try doing this and then figure out why a program has the bugs it does.
This is also the first step in being able to add your own secret cheats or hacks to the program. By breaking the program from what it normally does, you can learn how to change it to do something neat effect (like secretly giving you hints on how to solve the puzzle). Feel free to experiment. You can always save a copy of the unchanged source code in a different file if you want to play the regular game again.
In fact, if you’d like some practice fixing bugs, there are several versions of this game’s source code that have small bugs in them. You can download these buggy versions from http://invpy.com/buggy/memorypuzzle. Try running the program to figure out what the bug is, and why the program is acting that way.