" 'It's wire,' said the Senior Wrangler. 'Wire's something that you have to make. And there's wheels. Hardly anything natural's got wheels.'
'It's just that up close, it looks -'
'- all one thing, ' said the Lecturer in Recent Runes, who had knelt down painfully to inspect it the better.
'Like one unit. Made all in one lump. Like a machine that's been grown. But that's ridiculous.'
'Maybe. Isn't there a sort of cuckoo in the Ramtops that builds clocks to nest in?' said the Bursar.
'Yes, but that's just courtship ritual,' said the Lecturer in Recent Runes airily. 'Besides, they keep lousy time.'"
T.Pratchett, "Reaper Man"