A pneumatic boundary built from one Y-shaped cell tessellated into an 8×4 field. As the chambers inflate, neighboring arms press together and the openings close inward—an auxetic-inspired field that contracts rather than expands. Inflation is triggered by an EEG signal (frontal alpha asymmetry) read from one of two seated participants, so the boundary thickens and sightlines fragment in response to a withdrawal-leaning state.