From [[The Clock of the Long Now (Book)]]: When constructing the clock, consider choosing *a material that’s extremely brittle* because its weakness is actually a strength: It creates a binary situation: **The clock is either intact OR it has collapsed.** You always know if it’s broken or not because you can see it. There is no chance that slow, long-term loss creeps in that throws the system off slightly over time. You may think everything is fine because nothing looks “broken” but you may be already losing seconds or minutes or more! For brittleness to be a feature, you need a simple re-calibration method.