# Day 2, Matrices, matrices, matrices. Oh, and more matrices

Today was spent on a heavy chunk of linear algebra, matrices. This is the foundation for everything else, so time well spent reimplementing what’s already in the stdlib, just to refresh my math skills. If there are still days left of Devember when I’m finished, I’ll come back and replace all this with the stdlib implementation instead, hoping I’m somewhat close to the same API.

The next natural step, was defining the different transformations needed for all vector space calculations, and also happened to be the next chapter in the book.

Now we’re almost ready for some real action.

```
p = Point[0, 1, 0]
T = identity.rotate_x(0.25) # We're counting rotation in units of τ
T * p
=> (0.0, 0.0, 1.0, 1.0)
```

## Next related

### Day 3, Casting rays into spheres

Finally some practical applications of the math heavy weekend, casting abstract rays at abstract spheres. Well, on a sliding scale from linear algebra to physical representation, it’s still a step in the direction.

## Previous related

### Day 1, Overdoing it

The first proper day of Devember is here. Of course I overdid it and spent all day coding, instead of just that one hour.

### Day 0, Tuple Basics

Oops, I started a day early.

### Devember is Coming

It’s that time of the year again.