Dini's Surface or Twisted Pseudosphere

Written by Paul Bourke
October 1995

Surface of constant curvature (negative).

Named after Ulisse Dini

x = a cos(u) sin(v)

y = a sin(u) sin(v)

z = a (cos(v) + log(tan(v/2))) + b u

0 <= u, 0 < v

Appeared on the cover of the Graduate Study in Mathematics, Western Kentuky University.

Appeared on stickers for the MAA
(Mathematical Association of America).