Hi,

I have a quad mesh over 3 dimensions. I want normal vector for each element. I tried FacetNormal and CellNormal but doesn’t find how to output the normal vector.

```
from dolfinx import *
mesh = UnitSquareMesh(4,4) # consider 2D mesh for this case
n = CellNormal(mesh)
```

- get_local doesn’t work here to find vector components information.
- Where is normal vector defined? is it at all guass points or is it average of nodal normal vectors.
- Since, it is a 2-dimension element. How can I find the initial curvature of mesh element. Is here a way a function in ufl like director_vector() to find normal and curvatures?

Any help is greatly appreciated!