4.3 SIRDS


  Graph2D uses for the three-dimensional presentation of function a
technique known as SIRDS (= Single Image Random Dot Stereogramm). You do
not need special glasses or something like this, you may even print out the
pictures without loosing the effect.

  The only thing you have to do to achieve the 3D-effect ist to look at the
pictures in a special way. Instead of looking at the picture itself you
have to look behind the picture. Of course you will not see the random dots
sharp this way - but this is nescessary for the three-dimensionality.
  It may take sometimes until the effect is going to come, and for strange
reasons some people never get the "kick". For further instructions how to
achieve the effect please refer to the numerous publications concerning
SIRDS pictures.

  I want to thank Kilian Singer for his small but effective piece of code
that makes those pictures possible in Graph2D!