Top one looks like a slug that ran into a tiny tiny door, face first.
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If you want to know how well a broom works you do not ask the guy selling the broom or the guy who designed the broom, you ask the guy using the broom.
The top photo is is a shelter used by the Royal British Army. Just spray water on it and the concrete hardens in just a very short time. Probably Hi-Early Hi-strength Portland Cement Type II or III.
Voila, instant shelter, sort of!
Try taking that puppy down, fold it, and pack it into your ruck sack, eh?!!! No, you won't be humping it through the Boonies, up and down dale.
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"Veni, Vidi, Vici"; hendiatris attributed to Gaius Julius Caesar, 47 B.C.