Very neat. Alternative-length radians seem quite common. Radians are by definition one radius, but NATO mils are 0.00098 radii (and apparently the Finnish piiru are 0.00105 radii). What you describe are effectively a unit that is 0.0018 radii. Makes sense.

I see. Today I learned about piiru from you.

I do dislike the fact the libc sin takes argument in radians. For two reasons. One, the angles in the application are rarely in radians, so they need to be converted before the function call. Two, I would like the standard angles, such as the multiples of 15 degrees to have an accurate representation in 32 bits (or 64 bits).

Anyhow this is way off topic.