Lesson 13: PatternPainter

We have learned a lot of new terms so far! Let's review some of these terms through a game of CS Pyramid.

Group: Place students in pairs.

Do This: Review the instructions for playing CS Pyramid.

Do This: Play the music clip to cue the CS Pyramid activity, and direct students to play CS Pyramid. Click through the animated slide to display each pyramid, and direct students to switch roles with each new pyramid.

Our PainterPlus class allows us to navigate and paint The Neighborhood with additional methods, such as turning right. We currently have a one-to-one relationship between the PainterPlus and Painter classes, but we can expand this relationship to create an inheritance hierarchy with multiple subclasses.

Do This: Review the lesson objectives.

Do This: Define inheritance hierarchy.

Distribute: Give each student a copy of the PatternPainter handout.

Have students share a hobby or interest and ask how these might be represented as a symbol. Give an example of a hobby or interest and possible symbols that you might make into a pattern.

Discuss: Click through the animated slide to display the prompts. Use the Hold That Thought strategy to discuss the prompts.

• Why should we make a new type of Painter instead of adding methods for this problem to PainterPlus?
• Which should this new class extend – Painter or PainterPlus?

Discussion Goal: Students realize this class focuses on creating patterns, while the PainterPlus class provides additional behaviors for basic navigation and painting in The Neighborhood. Students suggest extending PainterPlus, so the new class has the same behaviors as the Painter and PainterPlus classes.

If students struggle to identify the need for a new type of class or to determine which class to extend, ask additional guiding questions and refer them to the UML diagrams on the Unit 1 Guide. For example:

• What is the purpose of the Painter class? How about the PainterPlus class?
• Why do we create subclasses?
• Should the new subclass have the same behaviors as the Painter class or the PainterPlus class?

We can create a PatternPainter class that extends the PainterPlus class. This class would have the same attributes and behaviors as both the Painter and PainterPlus classes, and we can specialize this type of Painter to focus on creating patterns.

Do This: Direct students to create a UML diagram for the PatternPainter class and write pseudocode for the methods to write.

When painting patterns and murals, we need a way to set the amount of paint a Painter object has so we don't have to collect a lot of paint from multiple paint buckets.

Do This: Introduce and explain the setPaint() method.

Use your UML diagram, pseudocode, and notes to create the PatternPainter class. After writing the class, create a mural of your pattern.

Do This: Direct students to Level 1 on Code Studio to complete Levels 1, 2, and 3. Students complete a Check for Understanding on Level 1, then continue to Level 2 to write the PatternPainter class. Students create a mural with their PatternPainter class on Level 3.

This is a good time to commit our code and save our PatternPainter class to the Backpack. Anytime we make changes to our programs, it is helpful to commit, or save, our work as a new version in case we need to revert to a previous version.

Do This: Play the music clip to cue committing their code and saving the PatternPainter class to the Backpack.

When we write new code, getting feedback from our peers is helpful to make sure we have met the requirements of the problem efficiently.

Do This: Click through the animated slide to have students participate in the Code Review Call and Response.

Do This: Direct students to complete a code review on their program on Level 4.

We have seen how computer science is used as a form of creative expression throughout the unit.

Discuss: What is the story behind your PatternPainter? What does the pattern it creates represent?

Discussion Goal: Students share their patterns and explain what they represent or mean to them.

Do This: Review the concepts covered in this lesson.

Display: Key Vocabulary

Check For Understanding Question(s) and solutions can be found in each lesson on Code Studio. You can use these questions as an exit ticket.

To assign questions from the AP Classroom Question Bank that align with this lesson, create a custom quiz in AP Classroom by searching the Question Bank for the Essential Knowledge statements listed at the top of this lesson plan. You can find instructions and video demonstrations to do this on AP Central.