Each book introduces a new fundamental computer science concept, with subsequent books spiraling back to previously-seen concepts and coding commands. Each set of books includes a unit-specific Educator's Guide with line-by-line code explanations, challenge solutions, and journaling suggestions for each app project.

Unit 2: Variables & Simple Methods introduces the use of placeholders for values and making code easier to change. The apps in Unit 2 illustrate the use of variables to store numbers, strings, booleans, and Bitsbox stamp objects. These projects also introduce the Bitsbox move, rotate, and size commands.

This book includes 10 open-ended projects, divided into 3 project types:

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How Do I? Apps

These examples answer common student questions about coding their own apps.

• Invaders From Space | 4 lines of code
  How do I move stamps to different places?
• Black Hole Blues | 5 lines of code
  How do I make a stamp disappear into a black hole?
• The Lonesome Yeti | 6 lines of code
  How do I make a stamp appear on the bottom half of the screen at a random size?

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Project Apps

These examples provide the code needed to build each app, along with challenges that enhance their understanding of the material.

• Getting Started Mini Apps | 3 + 4 + 3 lines of code
  These three super-short examples lay out the basics of using the text, .move, .rotate, and .size commands.
• Mars Needs Milk | 14 lines of code in 2 code sections
  Tap tap tap to suck cows into your flying saucer!
• Bedbug Bedlam | 12 lines of code in 1 code section
  Pop the never-ending bedbugs before they take over!
• Burnie the Artbot | 12 lines of code in 1 code section
  Draw with Burnie's super hot laser!
• Castle Defender | 15 lines of code in 3 code sections
  Create a castle to defend from the evil robot.

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Challenge Apps

No code provided! These examples challenge students to code an app based only on an image and a description of the final product.

• Draw with Droids | 6 lines of code (as assigned)
  Haven't you always wanted to paint a masterpiece with tiny bots?
• Welcome to the Wormhole | 11 lines of code (as assigned)
  Tap to send millions of giant-headed robots into the next dimension!

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