# Message #3929

From: Melinda Green <melinda@superliminal.com>

Subject: Re: [MC4D] Re: Notation

Date: Fri, 05 Jan 2018 14:33:53 -0800

From Wikipedia:

```
"a face is a flat (planar) surface that forms part of the boundary of a solid object; a three-dimensional solid bounded exclusively by flat faces is a polyhedron.
In more technical treatments of the geometry of polyhedra and higher-dimensional polytopes, the term is also used to mean an element of any dimension of a more general polytope (in any number of dimensions)."
```

We’re using the term in the second sense; specifically, the components of N-1 dimensions. Note that a 2x2x2 half puzzle is much more than a face but we are typically referring to the face that occupies the outer 8 corners of such a half. We’ll sometimes be loosely referring to that entire half puzzle when we should instead say something like "purple half", but it’s usually clear in context.

-Melinda

On 1/5/2018 9:26 AM, emil.indjev@gmail.com [4D_Cubing] wrote:

> Great post, though I don’t see how to notate a "whole cube reorientation". BTW you keep calling them faces, but the are whole cubes and are called cells.