Ever wanted to make Scratch draw cool shapes by writing your own code? This beginner-friendly tutorial shows you how to create polygons like triangles, squares, and pentagons, then turn them into colorful, interactive drawings using Scratch’s pen extension and sliders.

Watch this video for a step-by-step guide. This blog supports the tutorial by explaining the concepts and code behind it.

Draw Shapes like a pro in Scratch - Watch Now

What You’ll Learn

• How to calculate turning angles to draw regular polygons
• Using variables and sliders to control the number of sides, side length, color, and repeats
• Applying loops to repeat actions and create shapes
• Organizing code with custom blocks for cleaner projects
• Using Scratch’s pen extension to draw on the stage

Step-by-Step: Building the Project

We begin by understanding polygons: dividing 360° by the number of sides gives the angle to turn to close the shape. For example:

• Triangle (3 sides) → turn 120°
• Square (4 sides) → turn 90°
• Pentagon (5 sides) → turn 72°

With this formula, you can draw any regular polygon by moving forward and turning accordingly.

Next, we create sliders for:

• Sides: Number of sides of the polygon
• Length: Length of each side
• Color: The color of the shape’s lines
• Repeat: how many sides the shape has (the number of times we repeat drawing one side and turning)

Using a repeat loop, Scratch draws all the sides, and a forever loop lets the drawing update dynamically as you adjust sliders.

Key Programming Concepts

• Variable: Stores values like number of sides or color, allowing your code to change based on input.
• Loop: Repeats a set of instructions multiple times — here, to draw all sides.
• Custom Block: A reusable group of code commands that keep your project organized and modular.
• Pen Extension: Lets your sprite draw on the screen, controlling pen size, color, and erasing.

Troubleshooting Common Issues

• Shape looks incorrect? Check that 360 ÷ sides is correct and your repeat count matches the sides.
• Old drawings stay on screen? Use “erase all” before drawing new shapes.
• Sliders don’t affect drawing? Ensure variables are linked properly in your code.
• Forever loop slows project? Watch the next tutorial for ways to optimize loops.

Advanced Ideas to Explore

• Animate your shapes by rotating them slightly between repeats to create cool designs.
• Cycle or randomize pen colors for dynamic visuals.
• Use user input blocks to let others customize their shapes.
• Challenge yourself to recreate real-world signs or symmetrical art.

Don’t forget to watch the video above to follow along visually. This blog is made to support your learning experience!

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Finished This Tutorial?

Great job! In the next video, you’ll learn how to optimize the forever loop to avoid unnecessary redrawing while keeping your project interactive and smooth. This step improves efficiency and your coding skills.

If you liked this tutorial, subscribe to our YouTube channel for more hands-on Scratch projects that help you explore programming creatively and effectively. New tutorials are posted regularly!

Happy coding!
TheSTEAMist

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