I referencedthis photograph so I'm not accepting any responsibility for the geometry ;)
www.cnet.co.uk/i/c/blg/cat/blog/hair/hair_3.jpg
(www.cnet.co.uk/i/c/blg/cat/blog/hair/hair_3.jpg
Pasanonic 's been known to cause insanity in laboratory mice,
Wed 5 Nov 2008, 23:03,
archived)