Actually, the Shroud fascinates me - there are so many questions.
What do you mean when you say that it’s ‘natural’ and ‘unintended’?
It seems to me that both could be true, while the Shroud remained inexplicable by current science; and thus considered SUPERnatural.
I don’t really believe in the notion of ‘supernatural’ - if something happens, it’s Natural, though we may not understand it yet - but we’re stuck with the language, for now...
(I can’t remember who it was - perhaps one of the Huxleys - who said that if he saw something that seemed ‘supernatural’, he would not assume that it was so; but that it must have been operating according to a law that science simply hadn’t grasped yet.)
It's a long story, but if you're familiar with Ian Wilson's Shroud/Mandylion theory and have read the Byzantine history of the Mandylion it makes sense. Supposedly a King Abgar turned to Christianity following some sort of miraculous cure and having obtained the divinely-wrought image of Jesus on a cloth, placed the cloth above the city gates of Edessa to be venerated. Upon his death, his son reverted to paganism and ordered the image destroyed. Abgar's retainers, not wanting to destroy the image, bricked it up in a niche within the city walls. Six hundred years later, during the siege of the city it was discovered, along with a "tile" containing an exact duplicate of the image on the cloth.
If there's any truth to the story, it's my speculation that the original of the image was actually the tile, not the cloth, and that the cloth was meant as a covering for the tile. Over the course of hundreds of years, naturally-occurring radioactive material (the sort found in all sedimentary rock) gave off enough ionizing radiation to "slow-cook" the image onto the cloth.
And while none of this is miraculous, given the time involved, it means that the tile and the image contain a depiction of Jesus as he would have appeared to those who lived around the time of his mission. In the histories, Abgar was very particular about Jesus's appearance.
In my experience there are two attitudes toward the Shroud. One is that it is an utter hoax, and any attempt to explain it is a waste of time. The other is that it is an undoubted miracle that can have no natural explanation. One side is as pig-headed as the other.
Funny thing is that the fact that laws exist is supernatural in itself. A law must be written/ordained, they don’t just ‘happen’.