simple rope interpolation

float length = (dest.position-source.position);

for (int n=1; n < numBones-1; ++n) {

    float i = Mathf.InverseLerp(0,numBones,n);
    float si = Mathf.SmoothStep(i);

    float sourceLine = source.position + source.forward * length * i;
    float destLine = dest.position - dest.forward * length * (1-i);

    Vector3 pos = Vector3.Lerp( sourceLine, destLine, si);
    Quaternion rot = Quaternion.Slerp( source.rotation, dest.rotation, si);
}