SIN is a small ZZT maze game by the late Flimsy Parkins. While not originally uploaded to z2, it was recovered through the Internet Archive, and can be viewed and played on the Museum of ZZT.
It contains unusual board edge links, and no ZZT objects or text of any kind. Several inaccessible false paths give the impression that the world continues to sprawl beyond the confines of the existing boards. A single blank scroll ends the game on contact.
I made a full map which can be viewed here.