Create a reset function (15+ minutes):
2+ minute demonstration
Ask the class if they can explain how to get rid of all of the drawing on the screen by pressing a button. Demonstrate double clicking on the erase all block to erase the screen.

8+ minute coding time and 1-on-1 facilitating
Give the class time to see if they can create a function using message blocks or My Blocks that resets both the cat and screen, and figure out when they want to trigger that function.

5+ minute collaborative demonstration
Have a couple of people share with the class what they did to create a reset function. Display the reset function demonstrated in the quick reference guide. Have the class compare with a neighbor how the different algorithms performed the same task in different ways.

Video: Create a reset function (2:55)
Quick reference guide: Click here

Suggested questions:

• What kinds of blocks might we use to reset our cat?
  • What blocks have we used in the past to reset sprites in other projects?
• Could you add user controls to reset our simulator?
• What happens if you put the “erase all” block before using a motion block instead of at the end of the reset algorithm?
  • Why does it leave a streak of color when it resets?
    • It’s because it erases the drawing, but once the sprite moves to a new location it draws again if the pen is still down. Put the erase all block at the end to ensure it erases everything after it has moved.
    • Another way to prevent this bug is to use a pen up block before moving, then using a pen down block when finished with moving.
• When else might you trigger the “reset” function we created?
• Helpful hint: Each block color you use in your algorithms might have an option to reset something in that block type. For example,
  • Motion blocks can reset position, direction, etc.
  • Looks blocks can reset color, size, effect, etc.
  • Sound blocks can stop or reset music or sounds
  • Pen blocks can reset if a pen is down or up, erase the screen, set a color and size, etc.

Draw with the click of a mouse (10+ minutes):
8+ minute challenge
Pull up the example project and ask coders if they can figure out how to make it so the sprite draws only when the mouse is clicked.

Every couple of minutes, give one of the following hints:

• You will need to use both a pen down block and a pen up block
• You will need to use them inside of a loop
• You will need to use an if/else block
• You will need to use a mouse down? block

Bonus challenge if someone figures it out early: Try and figure out how to prevent the sprite from drawing as soon as the Green Flag is clicked.

2+ minute demonstration and discussion
Demonstrate how to use the if/else block as shown in the quick reference guide (as well as fixing the bug when the Green Flag is clicked). Reiterate that the if/else block will either run the code in the top half or the bottom half of the if/else block, never both.

Video: Draw with the click of a mouse (2:28)
Quick reference guide: Click here

Potential unplugged lesson: You could engage in a discussion or lesson on conditionals (if/else statements) by working through one of the unplugged lessons on conditionals; for example, Conditionals with Cards.

Advanced Note: We can stack multiple if/else blocks inside the “else” portion of the block to check several possible conditions (each “if” block) and execute one default (the final “else” block). Click here for an example where the text changes depending on how close you are to the goal, and click here to see the code in context.

Create a timer with variables (5+ minutes):
2+ minute demonstration
Demonstrate the “Counting up” example in the quick reference guide to demonstrate how to make a timer count up.

3+ minute coding time and 1-on-1 facilitating
Give time for coders to add in a timer if they so choose.

If you would like to demonstrate the advanced option in the quick reference guide, also demonstrate how to create a “Longest Time” variable (a practice common among Nyan Cat appropriations).

Video: Create a timer with variables (4:55)
Quick reference guide: Click here

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 ______?
• What other sprites can you add to your project?
• What have you learned in other projects that you could use in this project?
• Can you add user controls?
  • Examples: change the size of the drawing, change the backdrop or sprite, change the speed of the cat, press a button to reset the screen, etc.
• How else might you use pen blocks in your project?
• Could you turn this into a game by adding in other sprites as enemies or power ups?
  • Could you make this game have multiple levels or boss battles?
  • Could you make your game multiplayer?

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 could you add pen blocks to this project?
  • If they’re already using pen blocks, why do you think they used the blocks they have and not others?
• How might you add in a Nyan Cat to this project?