Today you are coding in Scratch. You will build a Pattern Creator step by step at your device.

You can already make a sprite move and turn. Today you will put those actions inside a loop so the pen draws circles, lines and spirals without copying the same blocks over and over.

Before you run anything, think: what might happen if the sprite keeps moving and turning a little bit each time?

To draw the spiral in this lesson, the ball has to move a little and turn a little, over and over, until it reaches the edge of the stage.

You could do that by dragging a move block and a turn block, then another pair, then another. A full spiral would take hundreds of them. And if you then wanted a different turn, you would have to change every single one.

A loop does the same job with one copy of each block. Change the block once and the whole pattern changes.

As you build, keep two questions in mind: what exactly is repeating, and what stops it?

Go to the Scratch website, create a new project and delete the cat sprite.

scratch.mit.edu/projects/editor

Scratch: How to create a new project

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Go to the Scratch website using the link below and click on the 'Create' link in the blue bar at the top.

By default, each new project starts with the cat sprite already added. To delete the cat click on the x in the blue circle beside the cat in the sprite list.

https://scratch.mit.edu

We are going to use the Pen blocks to create patterns but first we'll need to add a sprite that will do the drawing. It doesn't really matter which sprite we use as we are going to hide it.

Add the Ball sprite from the sprite library and then give it the following code.

when green flag clicked go to x (0) y (0) // we want to start it in the center hide

Scratch: How to add a sprite from the library

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To add a sprite from the sprite library follow these steps:

1. Put your mouse over the Choose a Sprite button
2. Click on the magnifying glass
3. Find the sprite you want in the library
4. Click on your chosen sprite

You can use search box or the filter links (Animals, People, Fantasy etc) to locate your sprite.

To draw the patterns we will be using the Pen blocks so add the Pen Extension to your project.

Once you've added the Pen Extension add the following new code blocks to the Ball sprite underneath the hide block.

when green flag clicked go to x (0) y (0) hide // add new code under here pen up // start with the pen up erase all // erase drawings from the last time set pen color to [#3438df] // choose a color pen down // put the pen down

Scratch: How to add extension blocks

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Understanding and Adding Extensions in Scratch

What are Scratch Extensions?

Scratch Extensions are additional sets of blocks that expand the capabilities of your Scratch projects. They allow you to:

1. Mention extensions like Pen here
2. Connect with external hardware (e.g., microbits)
3. Access web-based services (e.g., Google Translate, Amazon Text to Speech)
4. Use more advanced programming features

How Extensions Work

When you add an extension to your project:

• New blocks appear in the blocks palette
• These blocks are grouped under a category named after the extension
• You can use these blocks just like any other Scratch blocks

Adding an Extension to Your Project

1. Look for the "Add Extension" button in the bottom-left corner of the Scratch editor
2. Click the "Add Extension" button
3. A window will open showing all available extensions
4. Browse through the options or use the search bar to find a specific extension
5. Click on the extension you want to add
6. The extension is now added to your project, and its blocks appear in the blocks palette