Eierschwammerl (Pfifferling)

x(u,v) = (r + g(v)) cos(u) (1 - v) + v (R + g(v)) cos(u) y(u,v) = (r + g(v)) sin(u) (1 - v) + v (R + g(v)) sin(u) z(u,v) = v (a sin(n u) + h) + f(v)