" . . . behavior is not, what an organism does itself, but to what we point. Therefore, whether a type of behavior of an organism is adequate as a certain configuration of movements, will depend on the environment in which we de­ scribe it. " (Humberto Maturana, Francisco Varela: El arbol del conocimiento, 1984) "A thorough analysis of behavior must result in a scheme, that shows all regularities that are to be found between the sensorical input and the motorical output of an animal. This scheme is an abstract representation of the brain. " (Valentin Braitenberg: Gehirngespinste, 1973) During the 70ies, when Biomathematics (beyond Biomedical Statistics and Com­ puting) became more popular at universities and research institutes, the problems dealt with came mainly from the general fields of 'Population Biology' and 'Complex Systems Analysis' such as epidemics, ecosystems analysis, morphogenesis, genetics, immunology and neurology (see the first series of Springer Lecture Notes in Biomathematics). Since then, the picture has not considerably changed, and it seems that "a thorough analysis of behavior" of single organisms and, moreover, of their mutual interactions, is far from being understood. On the contrary, mathematical modellers and analysts have been well­ advised to restrict their investigations to specific aspects of 'biological behavior', one of which is 'biological motion'. Until now, only a few Conference Proceedings or Lecture Notes have paid attention to this important aspect, some of the earlier examples being Vol. 24: 'The measurement of biological shape and shape changes' (1978) or Vol.