Clay or Granite?

[Merry Christmas, for those of you who celebrate that. SMT will be going on hiatus until New Year's. Temporarily hiding comments too.]

Do you mold your ideas out modeling clay, or do you cut away the unnecessary parts from a solid mass of granite?

I prefer the first method, since it's less complicated, but often I find myself with a massive stone that I need to carve. In other words, an inchoate document with thousands of words concealing an article that needs to be written. In that case sometimes I just start over with a clean version containing only the actual sentences that say something intelligible.