1. Same glyphs, two 'x' in different spans with two different fonts. The primary font (AhemEx500) has a double aspect value (i.e., x-height/size = 0.5) of the secondary font (AhemEx250). The right glyph is adjusted with font-size-adjust: from-font, so it should be the same size as the left one.

2. Different glyphs 'x' and 'A' in the same span, with two fonts without font-size-adjust. As the primary font does not contain 'A' (U+0041), so the right glyph 'A' falls back to the secondary font. The right glyph should be smaller than the left one.

3. Different glyphs 'x' and 'A' in the same span, with two fonts and font-size-adjust: from-font. The right glyph 'A' cannot be rendered by the primary font, so it individually falls back to the secondary font. However, it should be the same size as the left glyph due to font-size-adjust: from-font.