Number 108 (Story #2), December 28, 1992 by Phillip F. Schewe and Ben Stein TUNGSTEN DISULPHIDE STRUCTURES can form closed concentric polygons and cylinders. Before now only carbon layered structures (e.g., Buckytubes) had been known to exhibit such closure. Scientists at the Weizmann Institute in Israel created WS2 concentric objects in sizes ranging from less than 10 nm to more than 100 nm. (Nature, 3 Dec. 1992.)