calling subclass constructor question

[In Han Kang]

So each of the sub classes plots a different type of graph.  The 
superclass defines methods that are the same for all the plots.  I want 
to be able to pick some points and be able to generate a more plots.  
What I was wondering if I could define in a method in the superclass of 
an object the ability to make a brand new subclass (new plot).  So 
basically, one plot makes another plot, but it'd be nice if i could put 
all the code in the superclass.

Thank you again for all your thoughts and helps.