Constant Curvature Space Curves

with torsion function tau(s) = a0 + a1*sin(s) + a2*sin(2s) + a3*sin(3s)

If a user chooses a0 = 0, a2 = 0, a3 = 0 then the program uses
tau(s) = a1*( sin(s) - 0.5*sin(3*s) + 0.1*sin(5*s).
The resulting curves have reflection symmetries and very stationary osculating circles.
Example: a1 = 1, kappa = 1, kappa adjusted.