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Lab 11: Recursion
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@section('content')
# Lab 11: Recursion
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## [Python Solutions](/content/labs/lab11_recursion/solutions)
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## [Worksheet Solutions](https://docs.google.com/document/d/1tR5-7mCEhw8EBwdqTI21QMREo0zNt-VzVcAUZmPN-ig/edit)
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## Summary
As usual, we'll work on this week's B notebook today. There are then 3 different options for Thonny activities to try: strings, turtles, and music.
@include('/labs/_setup', ['folder' => 'lab11_recursion'])
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+ Part 0: Non-fruitful warm up
+ Part 1: Non-fruitful recursive characters
+ Part 2: Fruitful recursion I
+ Part 3: Fruitful recursion II
+ Part 0: Worksheet
+ Part 1: Recursive Numbers and Characters (non-fruitful)
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## Videos
Here is the [youtube playlist with all the videos for this lab](https://www.youtube.com/playlist?list=PLX93PuaDL2dINYN5upQ10hIzk1smO1QqI). You can see the complete video list below, and videos are also embedded in lab web pages.
* (1/6) Worksheet Review Section 1 of 3 [](https://youtu.be/iiyGwGfii1I) | [Download](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_1_RecursionWorksheet1.mp4) | [Captions](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_1_RecursionWorksheet1.sbv)
* (2/6) Worksheet Review Section 2 of 3 [](https://youtu.be/4m0SQfP8BLU) | [Download](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_2_RecursionWorksheet2.mp4) | [Captions](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_2_RecursionWorksheet2.sbv)
* (3/6) Worksheet Review Section 3 of 3 [](https://youtu.be/-r0dqD5qJuc) | [Download](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_3_RecursionWorksheet3.mp4) | [Captions](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_3_RecursionWorksheet3.sbv)
* (4/6) Lab Tasks Part 1 asteriskTriangles [](https://youtu.be/PqLRfH1UDEk) | [Download](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_4_RecursionPart1.mp4) | [Captions](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_4_RecursionPart1.sbv)
* (5/6) Lab Tasks Part 2 Recursive Turtles Intro [](https://youtu.be/d2jYsQckEDE) | [Download](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_5_RecursionPart2Intro.mp4) | [Captions](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_5_RecursionPart2Intro.sbv)
* (6/6) Lab Tasks Part 2: doubleDiagonal [](https://youtu.be/mSJxupNHfbw) | [Download](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_6_RecursionPart2DoubleDiagonal.mp4) | [Captions](https://sakai.wellesley.edu/access/content/group/77109fc3-0650-48b0-aeb4-22c7e2e94cba/Lab%2011%3A%20Recursion/lab11_6_RecursionPart2DoubleDiagonal.sbv)
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@include('/labs/lab11_recursion/_toc')
## Big Questions {.bigqs}
- **How has your understanding of loops and repetitive actions changed since you started this class?**
Show "Answer"
There's no right answer here, but we hope that you feel you have a more
refined and explicit understanding of how repetitive processes start and
stop, and what kinds of patterns they might exhibit. It may not be obvious
(which is why we're asking this question), but by thinking a lot about
loops, and where they should start and stop, what should happen in each
iteration, etc., you are developing a new way to think about certain
problems. And we're about to do that again with recursion.
- **What is "wishful thinking?"**
Show Answer
Wishful thinking is when you assume that you have already solved a problem
before starting to solve it. It's a process of willing suspension of
disbelief, just like when you get absorbed in a good story and are willing
to excuse inaccuracies or exaggerations for the sake of the plot (except
maybe a little less entertaining and a little more deliberate). If used
carefully and with precision, it can be helpful in solving recursive
problems.
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