When you save a Simile model, it is saved as a text file in Prolog syntax. While it is not (and is not meant to be) human-readable, the format for this file is totally transparent. Anyone (with access to a Prolog programmer) can write programs for working with this file. One example is the Simile html model-description generator, a stand-alone Prolog program which produces an html file giving a complete description of any Simile model from the saved-model (.sml) file. This reflects our commitment to open modelling standards, with a variety of tools, produced by many different groups, for processing models in a variety of ways. Indeed, there is no reason why some other group shouldn't set out to produce a visual modelling environment that competes with, or complements, Simile itself!