>> Well, Metafont uses a third-order Bézier approximation to build up
>> circles (from four quarter circles). However, the Metafont book
>> says that the difference to a real circle is less than 0.06%, which
>> is thus imperceptible.
>>
>> The same holds for PostScript-based fonts.
>
> PostScript uses second-order Béziers, so it makes little sense to
> cite the mathematics of Metafont here.
This is not correct. PostScript-derived fonts (Type1, CFF/CFF2 in
OpenType) *do* use third-order curves. I think you are mixing this up
with TrueType fonts, which indeed use second-order curves.
Werner
