Inside every upside down box, there's a person.
Breakdown of inside
This clearly looks like an upside down box. Doesn't it?
Usages of inside
Inside a person, there's a lot of meat.
This term is more old-fashioned and formal, and it's often used by older men when referring to their own wives, particularly in formal or public settings. It carries a more humble and traditional connotation.
Note how the kanji in this word correspond to traditional gender roles. Therefore, younger people tend to prefer using the word 妻.
When one goes inside, one experiences only a third of the cold.