Meine heutige Stunde Erkenntnis und Unterhaltung auf dem Weihnachtssofa.

I think many people misunderstand the purpose of code review. The purpose of code review is not for the reviewer to find bugs, and certainly not for them to ensure that the code is bug-free. Anyone who depends on code review to find bugs is living in a fool's paradise. As everyone should know by now, it is not in general possible to find bugs by examining the code.
The primary purpose of code review is to find code that will be _hard to maintain_. The reviewer looks at the code and tries to understand what it is doing and how. If they can't, that means it will be hard to maintain in the future, and should be fixed now, while the original author is still familiar with it.
Additions with unique digits: A tale of puzzling and AI
The other day, Markus Krötzsch and I were catching up when one of his kids came in. She told us about a puzzle her math teacher gave her:
How many integer sums are there where the equation uses each digit at most once?
The simplest example is 1+2=3, but 12+47=59 also works. On the other hand, 1+9=10 isn’t a solution because the digit ‘1’ appears twice (in the first number and the sum).
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