In the 1985 work *'The Cat Who Walks Through Walls'* by Robert Heinlein, Richard Ames makes the following internal observation; The character is in an underground abode. The accommodations are in a side room off of a main corridor. The atmosphere is appropriate for shirt sleeves, think of it like being in a large mall with heat and air, low gravity being the only noticeable indicator you are not on Earth.

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> At one-sixth gee a rock shelf is softer than a foam mattress in Iowa. I went to sleep quickly.
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[(*Source*)](https://scifi.stackexchange.com/questions/57193/soft-as-a-rock-bed-on-the-moon-seeking-source-quote/57202#57202)

Would a lunar colonist find a rock shelf softer than a foam mattress? Would you only need a blanket and flat & level surface of solid rock to sleep comfortably in Moon's gravity?