Design is at the heart of vocational training programmes. That is the reason why teaching design and training students to design are major concerns of engineering schools. Our participation in this training favours a particular approach: reflexive practice. The Reflexive pedagogy lays the emphasis on the metaphorical dimension of learning. It is based on the idea that if the learner understands his/her own mental processes while learning, she/he learns better, by learning to learn. Reflexive thinking in our application is supported by a graphical representation. This graphic should enable the learners to turn the idea they are building up of their design activity into a kind of object. This article presents the reflective pedagogy that we have been using for several years now in collaboration with lecturers in technology to foster training in design for future engineers. (Contains 1 figure.)