The document describes how to code a maze game in Scratch. Students will create a game where a player guides an explorer character through a maze to rescue a friend. They will learn to use algorithms to design the code and implement conditional statements and loops to control the explorer's movement and make it interact with other sprites. The document provides algorithms for moving the explorer and making it rescue the friend, along with sample Scratch code, and guides students through tasks to build the game.

1. A Mazing Game

2. Starter Activity: Maze Games
Check out the maze style games:
http://scratch.mit.edu/tagged/shared/maze
A Mazing Game

3. A Mazing Game
In this lesson you will use algorithms to help code
a solution that uses conditional statements to
make a program loop. You will create a maze style
game.
Lesson
 Understand the use of an algorithm to develop a
solution to a problem
 Translate an algorithm into code
 Use conditional statements
Objectives

4. Introduction
You are going to create a simple game where the
player guides an ‘explorer’ character around a
maze using the arrow keys.
The game will end when the explorer rescues its
friend in the middle.
A Mazing Game

5. Watch the video Maze which is in the
programming in scratch folder in Groupwork to
learn how to create the game.
A Mazing Game

6. Task 6: Setting the Scene
Set up the game by importing the stage costume
(Maze) and two sprites – an explorer and a friend
for the explorer to rescue.
N.B The maze is already in the backgrounds folder
Don’t do any more at this point.
A Mazing Game

7. The Importance of Design
Before you make anything – a house, a car or a
computer program – you should start with a
design.
There are two important parts to most programs
– the interface (how it looks) and the code – you
design these separately.
A Mazing Game

8. The easiest way to design the interface is by
sketching it out on paper.
To design the code, the easiest way is to write out a
list of steps you want the code to perform in
English. This is known as an algorithm.
Algorithms let programmers concentrate on what
the code has to do, instead of how to do it on the
computer.
A Mazing Game

9. Designing the Solution
Think about the two main things that you will
need to code:
1. Moving the explorer around the maze
2. Getting the explorer to rescue its friend
The table on the next slide shows an algorithm for
moving the explorer around the maze and the
Scratch code that does the same thing.
A Mazing Game

10. Algorithm for moving explorer Code
when the flag is clicked
repeat forever
if right arrow key is pressed
point right
move 5 steps
if left arrow key is pressed
point left
move 5 steps
if up arrow key is pressed
point up
move 5 steps
if down arrow key is pressed
point down
move 5 steps
if explorer touches the same
colour as the maze wall

11. Task 7: Moving the Explorer
Using a combination of the algorithm and the code,
develop your game so that you are able to move the
explorer around the maze.
Use of the video is forbidden from this point
onwards.
A Mazing Game

12. Algorithm for moving explorer Code
when the flag is clicked
repeat forever
if right arrow key is pressed
point right
move 5 steps
if left arrow key is pressed
point left
move 5 steps
if up arrow key is pressed
point up
move 5 steps
if down arrow key is pressed
point down
move 5 steps
if explorer touches the same
colour as the maze wall

13. Test your game to see if it works
If it doesn’t see if you can identify the problem.
A Mazing Game

14. Task 8: Rescuing the Explorers Friend
From this algorithm, see if you can create the code
for the friend sprite!
A Mazing Game
Algorithm for reaching centre of maze Code for friend sprite
when the flag is clicked
show sprite
repeat forever
if touching explorer sprite
say “Thank you!”
hide sprite
stop all scripts
Code this one
yourself!

15. Test your game to see if it works
If it doesn’t see if you can identify the problem.
A Mazing Game

16. Plenary: Question 1
A programmer creates a
maze game like the one
you’ve just created.
Unfortunately, the
character doesn’t move
as expected.
What mistake has the
programmer made?
A Mazing Game

17. Plenary:
Look at the two
examples of
code.
Do they
perform the
same task?
A Mazing Game
Question 2

18. Plenary: Question 3
The code adjacent controls a sprite
going round a maze. If the sprite
touches the side of the maze (the
colour blue), it returns to its starting
position of -150, 150.
Unfortunately, the sprite sometimes
touches the walls of the maze and
returns to the start when the player
doesn’t expect.
What mistake has the programmer
made?
A Mazing Game

19. Plenary: Question 4
In this example, the sprite is
supposed to return to the centre
of the maze when it touches the
sides (coloured blue); however,
it only does this sometimes.
What mistake has the
programmer made?
A Mazing Game

20. A Mazing Game
Keywords
 Understand the use of an algorithm to develop a
solution to a problem
 Translate an algorithm into code
 Use conditional statements
Objectives
 Loop
 Sprites
 Interface
 Code
 Indented
 Conditional Statements
 Collision Detection
 Repetition
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