prison
囹 centers on confinement: a prison or jail, where someone is held within walls.
囹 combines the enclosure 囗 (representing walls or a boundary) with 令, which likely contributes a phonetic element. The character is used specifically for prison, suggesting a person confined within an enclosure.
The outer 囗 is a walled enclosure, and inside sits 令, like a command keeping someone locked up. Picture a prison cell with orders posted on the wall.
For レイ, imagine a prisoner laying in the cell: lay -> レイ, and the walls of 囹 keep them confined.
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