As one steps into Diagonal House, designed by Taiwan-based Studio X4, the first thing one notices is how the space seems to unfold around them, fluid and continuous, with the walls of the house guiding one’s movement. The diagonal partition of this private residence in Taipei is its defining feature. It cuts through the interior with a quiet yet commanding presence that not only separates spaces but also orchestrates the visual and physical movement within the contemporary residence. Public and private zones are no longer boxed in. Instead, they are connected and separated from each other via this single, deliberate gesture. The eye follows this curved axis instinctively, tracing how it shapes the layout without dominating it. Curved partition walls emerge as subtle companions to the diagonal, their smooth arcs softening transitions between spaces. These aren’t barriers but frames, defining the different areas within the residence, such as the living room, dining area, piano room, bedroom and study, without enclosing them.

Studio X4, founded by Taiwanese architect and designer Li-Yu Cheng in 2010, straddles various disciplines, such as architecture, interior design and furniture design, with an overarching interest in emulating and enhancing modernist architecture and contemporary design. The multidisciplinary team at Studio X4 is dedicated to understanding and integrating urban languages and interdisciplinary studies towards their spatial design practice. The studio’s work is prominently defined by monochromatic hues and the integration of curves, diagonally oriented layouts and rich textures. These definitive features are also visible within the studio’s latest work, Diagonal House.

Light becomes an active participant in Studio X4’s design—entering through gaps and seams to animate the residential interiors. In the early sketches for Diagonal House, the rigid diagonal had gashes through which light could trickle in, hence adding to the overall composition of the residential design. In the completed project, one can witness light dancing along the mineral-painted walls, accentuating their curves and textures. With the interplay of natural light and artificial light within the residence, the intensities and angles of which shift through the day, Diagonal House appears alive and responsive. The pendant light itself becomes a focal point underneath a triangular crevice as one steps in from the entrance. Light embalms the spaces through moments of contrast between light and shadow.

Walking through the private house, one is welcomed by the expansive living area, kitchen and piano room. This sets the stage for shared conversations and a sense of togetherness. The diagonal wall separates the public from the private, with the bedroom, study area, walk-in closet and washroom sheltered behind it. The directionality of the wall itself guides the residents towards the study and master bedroom itself. The two main zones—separated by the diagonally placed wall—further extend onto respective public and private terraces, making the residence more expansive. While the interiors grant a seamless passage for movement, a view of the outdoors from both the public and private zones allows the occupants to look out towards the sky. 

Furniture placement responds to this openness with care. The seating angles toward the diagonal, inviting conversation and movement, while the dining table anchors itself in the shared zone, perfectly aligned to catch the light that filters through the room. Even the study feels integrated, with its desk positioned to follow the axes, offering both privacy and a connection to the public zone. The colours are subdued yet rich, chosen to complement the natural tones of the materials. Earthy hues dominate, both on the ground and on the roof, grounding the interior in a palette that feels timeless and calming. These tones enhance the sense of continuity, blending seamlessly from one area to the next.

Textures play a quiet yet pivotal role in grounding the design. The mineral paint on the walls adds a tactile quality, its subtle grain catching the light and giving depth to the curves. Dark transparent materials appear strategically, particularly in areas like the walk-in closet and vanity, providing a sense of separation without severing the connection between spaces. This layering of textures creates a rhythm, an ebb and flow that mirrors the larger spatial transitions orchestrated by the diagonal.

This design’s brilliance lies in its ability to balance openness with intimacy. The absence of dominant walls allows air and light to circulate freely, yet every corner feels purposeful, crafted with an understanding of how the residents will inhabit it. The walk-in closet, for example, is positioned to offer privacy while still being visually linked to the bedroom through a translucent screen. The bedroom feels like a retreat, angled just slightly off the diagonal to create a sense of sanctuary without breaking the flow. Breaking away from the dominant direction helps define this zone spatially.

This project also shares a conceptual thread with Studio X4’s Museumism series—residential design projects with open-plan concepts where the focus lies on spaces that transcend conventional functionality to become experiential environments. Like its complimentary parts in the series, the Diagonal House explores how geometry, light, materials and textures can shape not just the physical layout but the emotional and sensory experiences of its occupants. The emphasis on axes, fluid transitions and the play of light and shadow ties it closely to this broader body of work, further showcasing the studio’s commitment to redefining how we perceive and inhabit space. The Diagonal House feels less like a space to live in and more like an experience to inhabit. It’s an environment that encourages you to move, to see, to feel—a home that redefines boundaries, not by erasing them but by reimagining how they can connect, guide, and inspire.

(Text by Arryan Siingh, Intern at STIR)