End-User Visual Languages as Guiding Lights to avoid Turing Tar Pit and its inverse

Nowadays, very different people use computer systems for their daily activities. This diversity of end users calls for general, adaptive systems. The temptation is to develop very general systems, which are Turing Tar Pits in which "everything is possible but nothing of interest is easy". The opposite temptation is to create overspecialized systems, in which operations are easy to perform but only specific activities, which cannot be generalized nor adapted and evolved, are possible; these systems may be considered as the inverse of Turing Tar Pits. This paper discusses an approach to creating interactive systems that are easily understood by end users because they "speak" end users' languages. Such visual languages are the "guiding lights" that prevent a system from being a Turing Tar Pit or its inverse