🧒 Explain like I'm 5
Imagine you have a Lego castle and you want to change one brick. Instead of breaking the whole castle, you take a photo of it, change just that one brick in the photo, and keep the old castle safe. That's what immutability does: it creates a new version with the change, but shares all the unchanged parts to save space and time.
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Senior-level deep dive: internals, pitfalls, and a self-interview ladder.
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