As I mentioned in my response, knowing that trees are used for various artifacts is important for the people who are implementing said artifacts.  A well done implementation hides that detail, focusing on ensuring the implementation is correct.  To use his analogy of Wehlings, there are standard procedures for blood transfusions, and the doctor doesn&#x27;t need to know about the heart, he just needs to know who to ask since he doesn&#x27;t work in a vacuum.<p>The other thing is that knowing a tree is symmetric and know how to reverse one don&#x27;t count as new and unknown challenges that author mentions. Both are well documented and easily accessible to anyone who needs to know that information.<p>I recently had an interview where I was presented with a problem the company had to solve.  That was new and exciting, not some minor detail from CS100 I learned years ago.