Have the number of files vary (or significantly increase it)

[NicMcPhee]

Students often end up really baking in the "there will only be three files" assumption in awkward and unhelpful ways. I wonder if we should either have the number of files vary (with some "magic" packet telling you how many files there will be), or just have it provide 100 files (most of which are very small to keep the time under control).