Make the Polaroids move (15+ minutes):
1+ minute demonstration
Without displaying the code, demonstrate how the Polaroids in the example project move around the screen before stamping on the backdrop.

9+ minute reverse engineering and peer-to-peer coaching
Ask coders to see if they can figure out how to use their code blocks to create an algorithm that makes a sprite do something similar to what was demonstrated. Facilitate by walking around and asking guiding questions.

1+ minute explanation demonstration
If coders figured out how to get their sprite to do something similar, have them document in their journal, share with a partner, or have a volunteer show the class their code and thought processes that led to the code. Otherwise, reveal the code, walk through each step of the algorithm, and explain any new blocks.

4+ minute application and exploration
Encourage coders to try something similar, and leave your code up on display while they work. Facilitate by walking around and asking questions about how coders might change their code so it’s not the same as yours.

Video: Suggestions for reverse engineering (4:25)

Video: Make the Polaroids move (2:25)
Quick reference guide: Click here

Alternative suggestion: If reverse engineering is too difficult for the coders you work with, you could display the source code and have coders predict what will happen.

Suggested guiding questions:

• What kind of blocks do you think you might need to do something like that?
• Do you see a pattern where we might use a repeat?
  • If so, what kind of repeat?
• When combining ideas, what happens if you use multiple event blocks in the same sprite? (Note: this concept is referred to as parallel computing)
  • What are the benefits/drawbacks of using multiple event blocks?

Potential discussion: There is not always one way to recreate something with code, so coders may come up with alternative solutions to your own code. When this occurs, it can open up an interesting discussion or journal reflection on the affordances and constraints of such code.

Suggested application and exploration questions:

• What other code blocks could you use?
• What other sprites might use similar code?
• What other code could we add to this project?
• Why do we need to add code to both sprites to get this to work correctly?

Start in a random corner (10+ minutes)
3+ minute demonstration
Pull up your own version of the example project and indicate that you want to make it so the Polaroid starts in a random corner of the screen. Create a new block called something like “go to a random corner.” Tell the class we want to make it so half the time it appears on the right side and the other half of the time it appears on the left side. To do this we are going to need an if/else block that picks random 1 to 2 and checks to see if the answer is 1. If the random number is 1, we will set x to -240 (left side of the screen); otherwise we will set x to 240 (right side of the screen).

6+ minute application
Keep the code up on the screen and ask the class if they can figure out how to make it so we have a 50/50 chance of starting at the top or bottom of the screen. Facilitate by walking around and asking guiding questions.

1+ minute explanation
Reveal the rest of the code on the screen and point out that the y coordinates are only -180 and 180 because the screen height is less than the width.

Video: Start in a random corner (3:26)
Quick reference guide: Click here

Suggested guiding questions:

• How did I make it so half the time it’s on the left and the other half the time it’s on the right? (pick random 1 to 2 = 1 inside an if/else block)
• Is the height of the screen the same as the width? (no)
  • What’s the highest and lowest numbers for the screen height? (180 and -180)
    • What motion block do we need to use to make the sprite appear at the top or bottom of the screen? (set y)
  • What’s the highest and lowest numbers for the screen width? (240 and -240)
    • What motion block do we need to use to make the sprite appear on the right or left side of the screen? (set x)

Add even more (30+ minutes, or at least one class):
If time permits and coders are interested in this project, encourage coders to explore what else they can create in Scratch by trying out new blocks and reviewing previous projects to get ideas for this project. When changes are made, encourage them to alter their comments to reflect the changes (either in the moment or at the end of class).

While facilitating this process, monitor to make sure coders don’t stick with one feature for too long. In particular, coders like to edit their sprites/backgrounds by painting on them or taking photos, or listen to the built-in sounds in Scratch. It may help to set a timer for creation processes outside of using blocks so coders focus their efforts on coding.

Facilitation Suggestion: Some coders may not thrive in inquiry based approaches to learning, so we can encourage them to use the Tutorials to get more ideas for their projects; however, we may need to remind coders the suggestions provided by Scratch are not specific to our projects, so it may create some unwanted results unless the code is modified to match our own intentions.

Suggested questions:

• What else can you do with Scratch?
• What do you think the other blocks do?
  • Can you make your project do ______?
• Can you make this project interactive?
• What else have you learned in other projects that you could use in this project?
• What other sprites can you add to your project?
  • Can you add sprites that match each Polaroid? For example, sprites that illustrate what happens in a project?

Similar projects:
Have coders explore the code of other peers in their class, or on a project studio dedicated to this project. Encourage coders to ask questions about each other’s code. When changes are made, encourage coders to alter their comments to reflect the changes (either in the moment or at the end of class).

Watch this video (3:20) if you are unsure how to use a project studio.

Note: Coders may need a gentle reminder we are looking at other projects to get ideas for our own project, not to simply play around. For example, “look for five minutes,” “look at no more than five other projects,” “find three projects that each do one thing you would like to add to your project,” or “find X number of projects that are similar to the project we are creating.”

Generic questions:

• What are some ways you can expand this project beyond what it can already do?
• How is this project similar (or different) to something you worked on today?
• What blocks did they use that you didn’t use?
  • What do you think those blocks do?
• What’s something you like about their project that you could add to your project?
• How might we turn this project into a scrapbook project?
• How could we save a copy of a project you worked on and add a narration of what you learned when creating this project?
  • Who could you share this project with?