The mutual school is based on peer learning. Invented in the 19th century to teach children to read, write and calculate, although it has shown its greatest effectiveness in terms of learning speed and cost (1 teacher for more than hundred students), frontal teaching was preferred in France the 28th june 1828 for political and religious reasons. It imposes a uniform rate of progression on all learner promotion. On the other hand, in several universities and schools in France, learning "at its own rhythm" is actually in use for theoretical or experimental works. The coupling between these two teaching approaches is experimented in 2020 in the context of a "theory of beam" course. The need to map learning paths, set up temporary student expert roles, help call systems within the group and use physical objects to represent the approach taken are detailed. In the tested case, only students of the same grade are present in the classroom. As a result, the teacher must ensure that the "expert time" given by the student is not too high for him/her to progress. The students' reactions and results are measured and analysed. During the poster session, the documents (text, videos and the physical objects) will be presented.