By John Teresko Stretch a rubber band and it becomes narrower in cross-section. However, that cause and effect isn't true in all states of matter, say researchers in Science, June 16, pages 2018-2022. They discuss counterintuitive possibilities in unusual states of matter where stretching causes lateral expansion. Expect the effect in either materials of very high density (neutron star crusts) or with low density substances (ion plasmas). For additional information e-mail Ray Baughman at Honeywell International Inc.