3D billboards are corner screens installed in large urban centres, impressive both for their size and the depth effect they create. With this project, we take on the creation for this device of a realistic content, designed for the night, that maintains the sensation of a strange discrepancy. The floating fabrics seem, at times, to step out of the frame, and the blue sky creates a striking contrast with the surrounding darkness. The light contributes to this visual integration, illuminating the fabrics with the brightness of day – but darkening them as soon as they approach the edge of the frame and the night outside. The sky at the top of the box finally opens up into an impossible space, offering an optical illusion in the manner of Escher.