A constant in our practice is ‘Verschränkte Plastik’. In English this can be translated as ‘Entangled Eidicity’. This is the principle we followed when designing the Chambord-stairs in Tridom Puzzle to entangle three apartments. Apartment means that we live apart from each other. However, together, in a same system. Through this spatial entanglement, a social relationship is translated in a tectonic form. The entanglement means a ‘sharing’ of infrastructures however keeping the division, the threshold between spatial entities – apartments. The geometry (double helix) allows the necessary separation of spaces with different ownerships.