README.TXT

To build a version of Component Cosmo that uses POLY21.DLL, copy 
the sources from CHAP13\COCOSMO and modify the function 
CCosmoDoc::FInit in DOCUMENT.CPP to use CLSID_Polyline19 
(it doesn't change from Chapter 21) instead of CLSID_Polyline10 in 
the CoCreateInstance call: 
 
Nothing else in CoCosmo needs to change to use the revised Polyline. 
Note that CoCosmo still uses the IPolyline10 interface on the Polyline 
object.  For all intents and purposes, nothing should change at all 
in the execution of CoCosmo, demonstrating how interfaces do not 
interfere with each other:  CoCosmo ignores the compound document 
interfaces.