Not Exact -F_xyz Spherical

Not Exact -F_xyz Spherical
In Tinkercad
https://www.tinkercad.com/things/4F1pUBxplEE
Related: (Not Exact -F_xyz Cylindrical)
Not exact cylinder -F_xyz.
https://www.thingiverse.com/thing:3071378
Related: (Not Exact -F_xyz Spherical)
Not exact sphere -F_xyz.
Not Exact -F_xyz Spherical (Similarity):
A + B = INFINITE,
a + b = finite (zero : 0),
a - b = -f,
b - a = +f,
(-f) + (+f) = 0 (zero : exact),
(-f) x (+f) = -F (not exact).