diff --git a/algorithms/oop.md b/algorithms/oop.md
index 54c32a4c..0df9cc2d 100644
--- a/algorithms/oop.md
+++ b/algorithms/oop.md
@@ -2,3 +2,7 @@ Object-Oriented Programming
 ==
 
 - How would you design a chess game? What classes and objects would you use? What methods would they have?
+- How would you design the data structures for a book keeping system for a library?
+- Explain how you would design a HTTP server? Give examples of classes, methods, and interfaces. What are the challenges here?
+- Discuss algorithms and data structures for a garbage collector?
+- How would you implement an HR system to keep track of employee salaries and benefits?