Olivier Gerard wrote: << I just spotted an old article of National Geographic http://news.nationalgeographic.com/news/2004/06/0624_040624_tvspider.html titled "New" Spider Species Weaves Uncommonly Regular Webs Reading the article, it seems the spider makes regular cells and put them together to match the place it wants to cover. . . . . . .

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I did not get the impression that a spider "spider makes regular cells and put them together . . .". Rather, from that & some other spider websites, I think all that "regular" means here is that the radii of an "orb" web tend to be approximately equally spaced -- i.e., at equal angles from neighboring radii. (In orb webs, the threads that are roughly perpendicular to the radii are described as spirals.) For reasons of structural efficiency, it seems plausible that the radii be at equal angles from their neighbors, and that the spiral be equiangular. --Dan