On regular and random two-dimensional packing of crosses

Abstract Packing problems, even of objects with regular geometries, are in general non-trivial. For few special shapes, the features crystalline as well random, irregular two-dimensional (2D) packing structures known. The 2D crosses does not yet belong to category solved problems. We demonstrate experiments different aspect ratios (arm width length) which fractions actually achieved by random packing, and we compare them densest structures. determine local correlations orientations positions after ensembles randomly placed were compacted plane until they jam. Short-range orientational order is found over 2 3 cross lengths. Similarly, spatial distributions neighbors extend crosses. There no simple relation between geometries peaks correlation functions, but some can be traced typical configurations.