# The Pyramid environment

The goal in this environment is to train our agent to **get the gold brick on the top of the Pyramid. To do that, it needs to press a button to spawn a Pyramid, navigate to the Pyramid, knock it over, and move to the gold brick at the top**.

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit7/pyramids.png" alt="Pyramids Environment"/>


## The reward function

The reward function is:

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit7/pyramids-reward.png" alt="Pyramids Environment"/>

In terms of code, it looks like this
<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit7/pyramids-reward-code.png" alt="Pyramids Reward"/>

To train this new agent that seeks that button and then the Pyramid to destroy, we’ll use a combination of two types of rewards:

- The *extrinsic one* given by the environment (illustration above).
- But also an *intrinsic* one called **curiosity**. This second will **push our agent to be curious, or in other terms, to better explore its environment**.

If you want to know more about curiosity, the next section (optional) will explain the basics.

## The observation space

In terms of observation, we **use 148 raycasts that can each detect objects** (switch, bricks, golden brick, and walls.)

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit7/pyramids_raycasts.png"/>

We also use a **boolean variable indicating the switch state** (did we turn on or off the switch to spawn the Pyramid) and a vector that **contains the agent’s speed**.

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit7/pyramids-obs-code.png" alt="Pyramids obs code"/>


## The action space

The action space is **discrete** with four possible actions:

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit7/pyramids-action.png" alt="Pyramids Environment"/>
