In the late 1940s, a zoology professor at the University of Tubingen, in Germany, was studying how spiders build webs. A problem was that the spiders he was studying, cross spiders (which we have here ...

This shows a cross-spider, Araneus diadematus, in its orb web. Like many spiders, this species produces several types of silk: a stiff kind for the radial spokes of the web, and a more flexible one ...