"an object-oriented program is a bunch of objects laying around sending messages to one another." -
http://www.fincher.org/tips/General/SoftwareEngineering/ObjectOrientedDesign.shtml Design is a process of modeling the problem domain into programming constructs. emphasis here is to keep the design process simple by minimizing the difference between the problem domain and software domain. - http://eventhelix.com/RealtimeMantra/Object_Oriented/object_design_tips.htm

http://www.codeproject.com/KB/architecture/OOP_Concepts_and_manymore.aspx