design
p22. vehicle
p27. formatting
p23 error
p6. Invoice TaxType
p19.Tax (polymorphism)
p25. Data Flag
p21. encryption
p20. save
p2. account undo
p1. stop watch
p24. CA
p11. Stock Broker
p3. DbCommand,DdConnection
p18. student course
p9. SADlg, CADlg, SADao,CADao
p14. Extendable Family
p4. Flow Chart Traversal , Pipes and Filter
p13. GameObject
p12. JobHandler
p8. Stack, List, Queue
p7. AccountType - multi dimension
p10. Account Enrichment
p5. Rule Engine
p16. Statemachine
p15. Log library
p17. clone
Vertical and Horizontal: Two Approaches to the Decorator Pattern