Cet article rend compte d'une expérience d'atelier d'art-plastiques mené hors-les-murs , auquel participaient à la fois des enfants de classe dite « banale » et des enfants inscrits en ULIS. Les auteurs souhaitent montrer comment un tel dispositif, pourtant fruit d'un « éclatement » momentané de l'institution, a pu paradoxalement favoriser que s'y inscrive un enfant détaché des exigences du lien social. En se fondant sur l'approche psychanalytique du groupe et la clinique des médiations thérapeutiques, les auteurs vont analyser conjointement les modulations de l'ambiance sensorielle du groupe et les déambulations en son sein d'un enfant en particulier, que les défenses autistiques avaient jusque-là exclu de toute possibilité de partage d'une expérience faite en commun. Nous verrons que c'est grâce à la présence médiatrice de l'objet artistique, et à sa résonance avec ces autres éléments co-créés que sont les enveloppes sensorielles et psychiques groupales, qu'une place a pu être ouverte à cet enfant, lieu potentiel d'une créativité collectivement reconnue comme telle. Les auteurs proposeront d'emprunter à la géométrie, le Tesseract , pour figurer au mieux les phénomènes d'emboîtements, d'étayage et de transformation que le dispositif a su provoquer sur les différents niveaux de temporalité entre cet enfant isolé et le groupe de ses pairs. À l'image des cubes du Tesseract, toujours à la fois contenus et contenants, cette expérience montre qu'une autre pensée de l'inclusion est possible, mettant l'accent sur la possibilité d'un « être ensemble » moins tributaire du mouvement qui va du pathologique vers la normalisation. This paper explores the relationship between the effects of group dynamics and engagement with art on the symbolization processes among children with autism spectrum disorder. The authors investigate how the participation of a mixed group of schoolchildren and their teachers in an art-based initiative could encourage the inclusion of children with special needs with their "ordinary" schoolmates. The researchers focused on the "sensory atmosphere" within the group, enhanced by the different senses (sight, sound, touch, and the body in movement) in a collective experience of creative transformations. The resulting hypothesis is that the simultaneous exposure to multi-sensory modalities, the sensory atmosphere , and to the group dynamics during the creative activity would motivate constructive encounters with children who had no access to language and were excluded from social bonding at school. The clinical participant observations were conducted in an art workshop outside the school with a mixed group of schoolchildren ("ordinary" and special needs) and their teachers. The modulations of the sensory atmosphere in the group and the ambulation of a particular child, whose autistic defenses had previously excluded him from any possible shared experience with his peers, were analyzed, using the psychoanalytic approach of group dynamics and the practice of art-mediation in group therapy. The artistic activities in and by the group made it possible, through the proposal of a created-to-create object operating as a transitional mediator, to (re)energize the modalities of communication and connection: on the intrapsychic level for each group member, and on the intersubjective level among all group members. The presence of the adults and the group dynamic fulfilled the functions of holding and containment for the joint emergence of a creative process and group psychic processes. The artistic object, as a third-party mediator to the mixed group members, and its resonance with other co-created elements emerging from the multi-sensory modalities during the creative engagement, enhanced a reassuring sound envelope and a familiar sensory atmosphere. The reorganization of the group dynamics, on both manifest and latent levels, allowed for a potential bonding experience, by indulging the group in a collective creative production. During the first session, a "getting-used-to" stage was identified. The children were invited to explore the art workshop that contrasted with the spatial-temporal organization in their classrooms. In the fourth session, the object of mediation allowed for the transformation of the archaic elements originating in the various sensory modalities into elaborated elements of a collective creation process. It operated as a script which would be taken up and re-addressed in the group. A progressive construction of stylistic differentiation at the end of this stage was identified as a potential engagement in the process of symbolization. The authors suggest the figure of the Tesseract , a four-dimensional object (the three dimensions of space to which time is added), to represent the phenomena of interlocking, scaffolding, and transformation of the bonding and connections that the art-based device was able to provide on the different levels of temporality, in the intrapsychic and intersubjective spaces, between this autistic child and the group. This figurability makes it possible to underline the role of the various sensory modalities in regards to the process of symbolization in the group, at the topographical (the space of the workshop) and topological (the deformation of the created-to-create objects) levels; both influencing and supporting the unconscious-preconscious passage of the sensory archaic elements to formal signifiers. Like the cubes of the Tesseract , always in process, both containing and contained, these clinical participant observations hope to show that another way of thinking about inclusive education is possible, which could emphasize the possibility of a "being together" that is less dependent on the movement from pathology to normalization. The process of transformation is based on the encounter between the "body of the creator" and the "body of the work" and is not only based on the two-dimensional data of the body-psychic relationship. The child with autistic spectrum disorder can initially be welcomed in his or her "sensorimotor anchoring" within a frame co-constructed by the adults who also participate in the group activities. He or she can temporally use the group psychic apparatus to experience the presence of the artistic mediation and the humanizing encounter of the other. [ABSTRACT FROM AUTHOR]