The real reason why outhouses are often depicted with crescent moons on their doors

Why DO outhouses classically have crescent moons on their doors or their sides? Is is an ancient hold-over from when boys outhouses had suns on them and girls had moons? Is it a decorative way of bringing in ventilation and light? Is it an allusion to "mooning?" A cut-out to act as a handle for opening the door?

Hah. The answer is far less interesting than any of that. But hey, did you hear about the time that a fart ended up getting 10,000 people killed?

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