Introduction
The practice of teaching is important but very complex and difficult (Leinhardt & Ohlsson, 1990): the teacher
must be able to continuously structure or restructure his or her knowledge in different ways in order to
adaptively respond to changing practical demands from moment to moment, adapting different semiotic
resources from student to student, and from class to class. We aim at using interactive rich-media
representations of teaching and online communication tools for the design of virtual settings to support
mathematics teachers in learning to do the practice of teaching. We used animated classroom stories1
as
reference artifacts to prompt discussion among teachers, engaging them in talking about the rationality they
invest in action (Herbst & Chazan, 2003). Although animations may reduce some degrees of complexity of
classroom interaction, they were designed in such way that eliminated noisy elements (often present in video
records of practice) helped teachers attend to important events of classroom interaction. We also embedded the
animations as reference points directly into the online discussion space. That original feature can make the
discussion among the participants more meaningful and in-depth.