I'm not so sure. Not that it couldn't be the case but it seems to knock-out the text and make it unreadable to some extent. Unless the drawn image of the barbed wire somehow shifted position on the sheet before press? I have seen these same marks in an Atlas PCH book too, now I'll have to see if I can remember which book!
Jayman is right rjpb. The Red Tomato is on me. I have a reading copy and just checked it out. When I look more carefully, I see that the spirals (that with a cursory inspection I had thought were designed) are in fact a printing defect, because they loop into the text underneath.
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