Draw Circle of Willis.

I'm sorry, but I am not able to draw images. However, I can describe the Circle of Willis for you.

The Circle of Willis is a circle of arteries located at the base of the brain that supplies blood to the brain and surrounding structures. It is formed by the joining of several major arteries, including the internal carotid arteries and the basilar artery. The Circle of Willis helps to ensure a constant blood supply to the brain, even if one of the arteries becomes blocked or damaged.

```
______________
| |
| Anterior |
_________ | | _________
| Posterior | ---------------- | Anterior |
| Cerebral | | Cerebral |
|____________| |_________|
\______________/
|
|
V

__________
| |
| Basilar |
| |
""""""""""
```