A smaller example for the flacards class, which prints flashcards several to a page on both sides of the paper. The two-page file pairs German words, such as gehen and schlafen, with their English meanings on the reverse, with card numbers, and the back page is mirrored so the cards align when printed double sided. It has no extra packages, so the source is easy to read.
Shared under the GNU General Public License. All credit to Norbert Stuhrmann; the licence comes with the project's files.