Cornucopia

The Surface given by the parametric equations

$$x = e^{bv}\cos v+e^{av}\cos u\cos v$$

$$y = e^{bv}\sin v+e^{av}\cos u\sin v$$

$$z = e^{av}\sin u.$$

References

von Seggern, D. CRC Standard Curves and Surfaces. Boca Raton, FL: CRC Press, p. 304, 1993.