The backups can contain multiple folders, subdirectories, and those can have the whole rule-based system applied.

In the Leopard Dock, my home folder appears as a bunch of stacked folder icons because that's mostly what it contains: other folders.

My Documents, Pictures, and Movies folders all contain mostly other folders as the first few items, alphabetically.

Each folder can contain an arbitrary number of files, and it can also contain other folders.

Photos can be added directly to the Gallery with a scanner or camera, as wll as by simply pointing it to a folder containing folders.

A folder can also contain other folders.

Each box contains folders that include résumés, head shots and other biographical information on the members of her talented cast.

The carton contained folders, scraps of paper, and a jumble of pamphlets and brochures about English churches.

The user would see a desktop that contained documents and folders, with different icons representing different types of documents.

ZIP file may contain one or more files or folders that may have been compressed.