New in Wolfram Mathematica 7: Comprehensive Spline Support  previous | next 
Generate Periodic B-Spline Curves
Periodic spline curves can be represented using options.
In[1]:=

Click for copyable input
Manipulate[

 Graphics[{Yellow, Blue, Thick, 

   BSplineCurve[pts, SplineDegree -> 3, SplineClosed -> True], 

   FaceForm[], EdgeForm[{Dashed, Red}], Polygon[pts]}, Frame -> True, 

  PlotRange -> 5],

 {{pts, {{-2, 2}, {0, 1}, {-2, 

     0}, {0, -1}, {-2, -2}, {-4, -4}, {2, -4}, {4, 0}, {2, 4}, {-4, 

     4}}}, Locator, LocatorAutoCreate -> True},

 "Alt+click to add points"]
Out[1]=