# Additional Challenge Question

**URL:** <https://forum.code.org/t/additional-challenge-question/26285>\
**Category:** CS Discoveries\
**Tags:** csd-unit-3-lesson-16\
**Created:** [April 11, 2019, 4:09pm UTC](https://forum.code.org/t/additional-challenge-question/26285 "2019-04-11T16:09:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ben\_kuehl](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@ben\_kuehl](https://forum.code.org/u/ben_kuehl)\
**Post date:** [April 11, 2019, 4:09pm UTC](https://forum.code.org/t/additional-challenge-question/26285/1 "2019-04-11T16:09:37Z")

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So on the lesson plan it says if students finish the unplugged activity early. You could challenge them to figure out a way to test if the shapes are touching even if they are drawn on a different line. I am wondering if anyone has a potential answer to this? I like this idea and will try to figure it out on my own here soon probably, but if anyone had an answer to that would be nice.

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**Author:** ![jold](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.code.org/jold/32/5811_2.png) [@jold](https://forum.code.org/u/jold)\
**Post date:** [April 16, 2019, 4:29pm UTC](https://forum.code.org/t/additional-challenge-question/26285/4 "2019-04-16T16:29:20Z")

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Here are a couple resources to check out that discuss this topic.

[https://code.org/curriculum/algebra/19/Teacher](https://code.org/curriculum/algebra/19/Teacher)

> **[Collision Detection](http://www.jeffreythompson.org/collision-detection/point-circle.php)**
>
> An online book about collision detection using Processing.