[texhax] \overline and \phantom

Paul Stanley paulrichardstanley at gmail.com
Wed Aug 1 15:57:31 CEST 2012

[...]
> something like that, basically \phantom{...} takes up the same space as
> ... would
>
> there are two variants as well, \vphantom who give the same height and
> depth, but no width, and \hphantom, that provide width but no depth or
> height.
>
> Note that none of the phantoms print their argument
>
>
> At the other end there is \smash, which is like \hphantom, but it also
> prints its argument

Could you provide examples of where \vphantom' and \hphantom' could be used?
I can only picture two dimensions on the page, height and width,
where does the depth fit into this?
Finally, where would smash be used?

Many thanks,
Paul