Amazing ice graffiti

[mercurial]

When Robert Baker went outside on Wednesday morning, he found his car had been sprayed with dramatic ice graffiti.

Frost had tagged the windscreen and roof with the characteristic fronds and swirls of fern frost, which forms during the coldest nights.

Link

 

[Phronesis]

Interesting ice formations. How does one exclude the possiblity that those were not the product of mind (say a person came and formed those using the conditions and the properties of the metal and glass through whatever means during the night)? On the flip side, how does one confirm that those were indeed the product of mind if no one is suspected?
Take the following examples of ice formations. Which ones do you think can safely be ascribed to nature and which ones can be safely ascribed to be the product of mind. Which method would be approriate and how did you come to your conclusion?
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