Kyoto Box - Cardboard Oven

Detailed pic - structure

Perhaps more of a long term survival tool if the gas/juice stops flowing for a while. But I can think of a few times where building something like this out of trash or bits pulled from your wrecked vehicle could come in handy. And I gotta think that done right, it would make a good basis for a water still in a salt water or polluted water situation where boiling won't cut it.

A field-expedient version might just be too weak or hard to build. Anyone tried anything like this from scraps?
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Experience is a hard teacher because she gives the test first, the lesson afterwards.