2-3 hours for kids with basic scratch experience
Introduction
Drawing Patterns with Loops in Scratch
What We'll Create
In this project, we'll create a cool pattern using loops! Our sprite will draw a pattern that looks like a bunch of squares that get smaller and smaller, creating a spiral-like effect. By the end, you'll understand how to use loops, pen blocks, and basic movement in Scratch.
Step 1: Setting Up Your Canvas 🎨
Open Scratch and create a new project
Find the perfect backdrop:
Click the "Choose a Backdrop" button (bottom right)
Type "grid" in the search box
Select "Xy-grid-30px" - this will help us see our pattern clearly!
Step 2: Choose Your Artist 🎾
Let's get rid of the cat and pick a ball instead:
Click the "Choose a Sprite" button
Search for "ball" and select the tennis ball
Make your ball the right size:
Find the size setting in the sprite info section
Change it to 50
Drag your ball to the center of the stage
💡 Fun Tip: Feel free to customize your ball's look in the Costumes tab!
Step 3: Get Your Drawing Tools Ready 🖌️
1. Add the Pen extension:
Click "Add Extension" at the bottom left
Find and click on "Pen"
Look at all the new blue blocks that appeared - these are your drawing tools!
Step 4: Create the Pattern Code 🎯
Now for the fun part! Here's what our pattern does:
1. It draws a special square where two sides are shorter than the others
2. Each new square gets smaller than the last one
3. The pattern keeps going until the squares become tiny!
Important Parts of Your Code:
Start with a clean canvas:
Add a "when green flag clicked" block
Add "erase all" from the pen blocks
Add "pen up" (we don't want to draw yet!)
Get to your starting position:
Move your sprite where you want to start
Now add "pen down" (time to draw!)
Set pen color and pen size as per your choice
Create the loop:
Your main loop will repeat until the squares are very small
We can do this by looping 20 times
We can use size as the starting "length" of our square. Create a new variable called "size":
Click on "Variables" in the blocks palette
Click "Make a Variable"
Name it "size"
Click OK
In code, use "set my variable" block to set the variable to value 200
For drawing, we will need to draw squares. For each square:
Move forward
Turn 90 degrees
Do this 2 times (use a loop)
Make the next side a bit shorter (change size by -10). Draw the next 2 sides
Add a small wait (0.5 seconds) to watch your pattern come alive!
You have two loops - repeat "20" times and repeat "2" times
Add space bar handling to clear the screen (handle when space key pressed)
Check the code below if you are not able to do it yourself
Understanding What's Happening
Draw first side: moves forward by 'size' steps (starts at 200)
Turn right 90 degrees
Draw second side: moves forward by 'size' steps
Turn right 90 degrees
Change size to 'size-10'
Draw third side: moves forward by 'size' steps (shorter!)
Turn right 90 degrees
Draw fourth side: moves forward by 'size'
Turn right 90 degrees
Continue the loop
Make It Your Own! 🌈
Here are some cool ways to customize your pattern:
1. Try different colors or pen size after every loop
- Use "set pen color to" blocks
- Change colors inside your loop
2. Experiment with:
- Different starting positions
- Various square sizes
- Different turning angles
- Speed of drawing (change the wait time)
Troubleshooting Tips 🔧
If your pattern looks wrong, check:
Is your pen down when it should be?
Are your turn angles correct?
Is your sprite the right size?
Added the Pen extension
Put "pen down" before drawing
Clicked the green flag to start
Challenge! 🌟
Can you modify the pattern to:
- Draw circles instead of squares?
- Create a different spiral pattern?
Remember: There's no "wrong" way to make art - experiment and have fun!