This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
We can consider easily a couple of marginal cases that quotes are not pairing up perfectly. How would the transformation be asked to behave is uncertain as the question is not posed in a general setting... Here is one way that has one marginal behaviour rather than anything else.