Agreed, reminds me of a test I took in a stress analysis class (mechanical engineering at Arizona State University in the US). We had covered thermal expansion

Agreed, reminds me of a test I took in a stress analysis class (mechanical engineering at Arizona State University in the US). We had covered thermal expansion of unconstrained objects, as well as those held in certain dimensions by fixed walls. On the exam the professor wanted to cover both so he had the walls placed a small distance away. Most students flipped out because they had not seen an example of that exact situation, but a moment of thinking shows that the problem should be broken into pre-contact an post-contact parts. This professor had the highest drop rate I have seen (around 30%), but his insistence on comprehension over memorization made me learn more than any other class I took. Mobile submission, so please excuse grammar.