Writing, for me, is a little like wood carving. You find the lump of tree (the big central theme that gets you started), and you start cutting the shape that you think you want it to be. But you find, if you do it right, that the wood has a grain of its own (characters develop and present new insights, concentrated thinking about the story opens new avenues). If you're sensible, you work with the grain and, if you come across a knot hole, you incorporate that into the design. This is not the same as 'making it up as you go along'; it's a very careful process of control.
Terry PratchettNo matter what she did with her hair it took about three minutes for it to tangle itself up again, like a garden hosepipe in a shed [Which, no matter how carefully coiled, will always uncoil overnight and tie the lawnmower to the bicycles].
Terry PratchettI would like you to teach [the orcs] civilised behaviour," said Ladyship coldly. He appeared to consider this. "Yes of course, I think that would be quite possible," he said. "And who would you send to teach the humans?
Terry PratchettThe girls were expected to grow up to be somebody's wife. They were also expected to read and write, those being considered soft indoor jobs that were too fiddly for the boys.
Terry Pratchett