A Minimal Surface given by the parametric equation
References
do Carmo, M. P. ``The Helicoid.'' §3.5F in
Mathematical Models from the Collections of Universities and Museums (Ed. G. Fischer).
Braunschweig, Germany: Vieweg, p. 47, 1986.
Lichtenfels, O. von. ``Notiz über eine transcendente Minimalfläche.''
Sitzungsber. Kaiserl. Akad. Wiss. Wien 94, 41-54, 1889.