the staircase always looks like an interesting collection of layers to me

the series of Fire-exits. It's interesting how the emergency exits are generally labelled "fire exit" in the UK: it naturally hints how most of the emergent situations are related to fire.

→
→
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Japan, in contrast, just happens to have any kind of natural disaster you may have to escape from: which may be the reason why they are all labelled "emergency exit" instead of naming a specific emergency situation.