What do I mean by a compound? By compound I mean a glyph which presumably is not fundamental (like an atom) but instead the result of the blending together of two or more types of glyphs (like in a chemical compound). A compound is not a mixed glyph because some or all of the glyphs are shown only partially. Example:

I believe this glyph is made by fusion between these two types of glyph:

Compounds are often difficult to 'see through', when the glyphs partaking are shown just by a little sign.