The Fables project is grounded on an ecological approach to e-learning, where we analyze the practice of e-learning as an information ecology, centered on the interaction among teachers, pupils and their tools, placed within the classroom. A simple Fable represents one of Schön’s exemplars; a Fable can be interacted with digitally, as a simulation, to help understand and predict the behavior of a real-world system or scenario. In schools Fables can be used to represent the knowledge that pupils have, to be shared/showed interactively to others, and they are experienced as a more dynamic version of presentation slides. In this paper we strengthen the formal definition of Fables, and we investigate Fables’ expressive power. A new version of the online Fables tool F4BL3s has been implemented and used in the evaluation. The main new features of this version are: better visualization of Fables in playback, possibility for the authors to associate custom images to the characters in their Fables, and new export functions to convert a Fable into Twine stories and Microsoft PowerPoint compatible slides. According to our knowledge of the needs of teachers and pupils, the last feature is needed to improve interoperability of F4BL3s with other standard tools, which is in turn a key factor for the acceptance of the tool. Future work includes an improved visual editor as suggested by the data from our evaluation, and continue in-classroom tests.