The Invent with Python Blog

Writings from the author of Automate the Boring Stuff.

Code Comments Tutorial: Slide Puzzle Game

Fri 08 October 2010    Al Sweigart

Welcome to the Code Comments Tutorial for Slide Puzzle. Code Comments is a series of simple games with detailed comments in the source code, so you can see how the game works.

The text in between the triple-double-quotes are comments (technically they are multi-line strings, but Python uses them for multi-line comments). The Python interpreter ignores any text in between them, so we can add any comments about the source code without affecting the program. In general for Code Comments, the comments will describe the lines of code above the comment. It helps to view this file either on the Code Comments site or with a text editor that does "syntax highlighting", so that the comments appear in a separate color and are easier to distinguish from the code.

This Code Comments assumes you know some basic Python programming. If you are a beginner and would like to learn computer programming, there is a free book online called "Invent Your Own Computer Games with Python" at

The Code Comments programs make references to sections of this book throughout the program. This Code Comments can also teach you how to use the Pygame library to make your own games with graphics, animation, and sound. You can download Pygame from and view its documentation.

You can make some easy modifications to the game by changing the all-caps constant variables (such as BGCOLOR, COLS, ROWS, TILESIZE, etc.) This code uses global variables instead of object oriented programming in order to make it simple to understand.

Screenshot of Slide Puzzle game

Slide Puzzle source code with comments.

Slide Puzzle source code without comments.

Slide Puzzle .exe executable Windows binary (no need to download Python & Pygame)

How To Play Slide Puzzle:

There are 15 boxes in a 4x4 grid. At the start of the game, the boxes are randomly switched around the board to generate a new puzzle. When the puzzle is ready, start sliding around the boxes to reorder the boxes.

Learn to program for free with my books for beginners:

Sign up for my "Automate the Boring Stuff with Python" online course with this discount link.

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