DESCRIPTION 

Similarly mathematic surfaces can be visualised. 

PROCEDURE 

 1.Create a parametric point grid with varying domain and resolution  
2.Calculate for each point its distance from the origin = vector length  
3.Use this length as input parameter for an expression  
4.Move the point grid up acc. to these values  
5.Create a surface from these points. Note input parameter u which requires the number of points in the u-direction to be specified