display window geometry (position, size) while resizing or moving

[Robert Fleming]

Anyone know of a way to display a window's geometry (e.g. 80x24 characters
or 400x300 pixels) while the user is resizing/moving the window?

Here's FVWM doing it:
http://imgur.com/hu6rFrC

twm and Openbox also do it.

Thanks,
Robert