[math-fun] 3-D spider webs?

Olivier Gerard wrote:

Hello,

I just spotted an old article of National Geographic

http://news.nationalgeographic.com/news/2004/06/0624_040624_tvspider.html

[etc.] The movie "The Last Mimzy" featured a boy who, under the influence of various pedagogical artifacts from the future, creates a prize-winning science fair project by inducing spiders to build three-dimensional webs. Do any spiders build genuinely three-dimensional webs? (I am not counting random amorphous webs like the ones described in http://www.nytimes.com/2007/08/31/us/31spider.html?_r=1&oref=slogin but webs whose three-dimensionality is architectural.) Jim Propp