Final answer:
The detail that reveals the difference between the looking-glass land and the real world is the consistency of signpost directions.
Step-by-step explanation:
The detail from the excerpt that best reveals that things in the looking-glass land are not the same as in the real world is: Both signposts point in the same direction, even when the road splits in two. This detail suggests that the signposts in the looking-glass land do not provide accurate directions compared to the real world, where signposts would point in different directions when the road splits. This inconsistency indicates that the looking-glass land operates under different rules and logic.
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