The LaTeX 2.09-based program SliTeX, and the corresponding LaTeX slides class, use invisible fonts when producing multi-coloured overlays on foils. SliTeX distributions included a set of invisible versions of the MetaFont sources of the Computer Modern fonts (an odd concept, but it worked). The present bundle provides a (somewhat more intellectually satisfying) set of virtual fonts that provide the same information (i.e., effectively metrics only) without the need to compile a MetaFont source to get it.

The author is Armin Koellner.