# Spatial pooler and 2D input

**URL:** <https://discourse.numenta.org/t/spatial-pooler-and-2d-input/4703>\
**Category:** Engineering\
**Created:** [October 11, 2018, 10:02pm UTC](https://discourse.numenta.org/t/spatial-pooler-and-2d-input/4703 "2018-10-11T22:02:19Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![rhyolight](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.numenta.org/rhyolight/32/3922_2.png) [@rhyolight](https://discourse.numenta.org/u/rhyolight)\
**Post date:** [October 12, 2018, 1:06am UTC](https://discourse.numenta.org/t/spatial-pooler-and-2d-input/4703/2 "2018-10-12T01:06:59Z")

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This may or may not answer your questions, but it is a good introduction to the complexity topology introduces.

> [@Thoughts about topology](https://discourse.numenta.org/t/thoughts-about-topology/1631):
>
> I wanted to talk a bit about using topology with HTM. Most of this is just me working these thoughts out in my head, so some of it might be confusing or inaccurate. I welcome feedback and discussion. With no topology (the default today in NuPIC), the input space for the Spatial Pooler contains cells with no relationships to each other. The state of any bit in the input will never be correlated to the state of any other bit in the input. With topology enabled, the Spatial Pooler will calculate “…

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