Spinning Loops into Patterns

Last time, loops drew neat shapes. Today they make patterns — the kind that look like they took hours but are really just a few lines. The trick: repeat something, but turn a little between each repeat.

A star from one loop

Draw a long line, turn 144, repeat 5 times. Watch:

 
 
  

A five-pointed star! You didn’t tell it to draw a star — it appeared from “go forward, turn 144, repeat.” Small rules, surprising results.


Try it 🎯


    

  1. Change 144 to 170. Different star.
    2. 

  2. Change to 100. Try 160.
    3. 

  3. Change range(5) to range(9) with right(160) for a many-pointed burst.
    4. 



A burst of lines


Draw a line out and back, turn a tiny bit, over and over — a sunburst:


   
   
 
 
 
 
 
  

36 lines, each turned 10 from the last (36 × 10 = 360, a full circle of lines).


Predict it 🔮


What if you change range(36)/right(10) to range(12)/right(30)? Fewer lines, but do they still spread all the way around? Guess, then try it. (Yes — 12 × 30 still equals 360.)


A loop inside a loop


Here’s the showstopper. What if each repeat draws a whole square, and we turn a bit between squares? That needs a loop inside a loop — one to draw the square, one to spin it around:


   
   
 
 
 
 
 
  

Read the indentation like nested boxes: the inner loop (more indented) draws one square; the outer loop runs that 12 times, turning 30 between each. A beautiful rosette in six lines.


Try it 🎯


    

  1. Change range(12) to range(18) and t.right(30) to t.right(20).
    2. 

  2. Change the square’s forward(80) to 60.
    3. 

  3. Bold idea: change the inner loop to draw a triangle (range(3), right(120)) instead of a square.
    4. 



Fix the bug 🐞


This is meant to be a rosette, but the last turn got left out of the loop, so every square lands on top of the last one. Add the missing turn so the squares spin around. (Hint: it needs a t.right(30) inside the outer loop, after the inner loop.)


   
   
 
 
 
 
 
  

(Add     t.right(30) as the last line, indented to match for side — so it’s inside the outer loop but outside the inner one.)


Mix it up 🎨


Take the star at the top and wrap it in an outer loop that turns a little each time. Tiny changes, totally different art. Try this and then tweak every number:


   
   
 
 
 
 
 
  

Your mission 🚀


Invent your own pattern. Start from any example above and change the numbers until you get something you like. Try changing: the shape (square/triangle/star), how many times it spins, the turn between spins, the size, and the color. Save the numbers that made your favorite!


What you learned today


    

  • Repeat a shape while turning between repeats to make patterns.
    • 

  • Tiny changes to the numbers make wildly different art.
    • 

  • A loop inside a loop (nesting) repeats a whole shape many times.
    • 

  • Indentation decides what’s inside which loop.
    • 



Right now you change a pattern by editing numbers in lots of places. Next time, variables let you change one number and update the whole drawing at once. 🐢
   
 
 
 
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