Recently stumbled upon this Technifex promotional video, featuring Nostramos in a crystal ball just after the 1 minute mark:

The reel is promoting their “Techniscan” process, a version of the classic Pepper’s Ghost optical effect using a video screen.  This technique was used not only in the “Shrinking Northrup” sequence of Laboratory, but also in Nostramos’ magic mirror.  The rippling background was “practical,” meaning an actual piece of cloth with a fan and lights, while Nostramos was “projected,” in this case a reflection from a video screen.

What’s intriguing about this video is Nostramos appearing inside a crystal ball.  It’s unclear whether this was an early idea that the mirror later replaced (perhaps getting a crystal ball big enough would break the budget?), or if Technifex is merely using Nostramos as “test footage” to try out their Techniscan process in a sphere.