A perfectly symmetrical mansion is like a blank page, but the real story starts in the shadows. Keep the façade crisp—stucco, pointed arches, crisp stonework—so anyone passing by thinks it’s a relic of some forgotten era. Then, in the hidden rooms, let the walls breathe with whispers and flicker with lanterns that never die. The key is contrast: the calm of the exterior against the unsettling pulse inside. It’s a delicious paradox, and that tension is where the true horror lives.

Great, let’s sketch the core. Keep the façade a flawless rectangle with identical towers on either side, each topped with a spire that points straight up. Inside, the corridor runs the exact same length, but at the midpoint, a door opens to a room that’s slightly larger—just enough to throw off the symmetry. That room could have a central chandelier that’s oddly tilted, as if a wind of unseen breath is blowing through. The walls of that room might be lined with old portraits whose eyes seem to follow you, and the floorboards that creak at irregular intervals. In the other rooms, keep the layout identical, but add a faint, rhythmic thump in the walls—like a heartbeat that’s always just a step behind your pulse. The result? From the outside, a perfect, serene manor; inside, a maze of almost-but-not-quite symmetry that makes you feel like the building itself is alive and counting you.