Or simpler: you solve problem X, making you code as clean, documented, and extensible as you can. Then a team member has to extend it to solve X', where X' is

Or simpler: you solve problem X, making you code as clean, documented, and extensible as you can. Then a team member has to extend it to solve X', where X' is designed to show up bugs in the solution for X (turkish language insteadof english, etc).