This article is about maintaining cloud servers but contains an important lesson for educators as well, because educators often approach teaching as though they are in some way 'programming' their students. What happens when things randomly change? "We rightly dismiss the absurd and handle the mundane. However, human judgement fails quite badly when it comes to unlikely events.... Developers have generally been poor error handlers since development began." What you need to do is build in the likelihood of random failure from the outset. That's what Starling Bank did - they wrote a script that would randomly crash one of their cloud servers. The result was that developers, knowing that this would happen, had to build resilience into their systems. For educators, this is like building scenarios into their teaching such that whatever the student has learned will fail. How do they then respond? That's where real teaching begins.