ՆկարագրումClosed Surface.svg	Mesh drawing of a closed surface, given by the equation: ${\displaystyle z=-x^{2}-y^{2}\,}$ This was plotted in Mathematica and traced using Inkscape to give a smoother result. The Mathematica code is given below. This drawing is one in a series.
Թվական	13 Ապրիլ 2007
Աղբյուր	Own drawing, Inkscape 0.45
Հեղինակ	Inductiveload
Իրավունքներ (Նիշքի վերաօգտագործումը)	Public domainPublic domainfalsefalse I, the copyright holder of this work, release this work into the public domain. This applies worldwide. In some countries this may not be legally possible; if so: I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

Other Images in the Series

• 
  Open Surface
• 
  Flat Surface
• 
  Closed Surface

Mathematica Code

Plot3D[
  - x^2 - y^2,
  {x, -1, 1},
  {y, -1, 1},
  PlotRange -> All,
  Axes -> False,
  Boxed -> False,
  Shading -> False,
  PlotPoints -> {15, 15},
  ViewPoint -> {1.3, -2, 1},
  ImageSize -> 300]