Sure, let’s start with a circular keep at the centre, because symmetry keeps the mind from wandering. Wrap that with a double‑layered wall, the inner one at 30 m thick, the outer at 20 m, so that a single breach is enough to bring the whole thing down. Dig a moat 15 m wide, keep it filled with water from the eastern spring, and install a single drawbridge that folds into a hidden recess for a quick escape. Inside, lay out three concentric rings of rooms: the innermost for command and living quarters, the middle for storage and workshops, and the outermost for the farms and granaries. Connect each ring with a narrow, single‑passage corridor that’s only 3 m wide—enough for a man but narrow enough to force a defender to keep an eye on the front. Place the resource chambers—fuel, iron, food—behind the outer wall, each sealed with a steel door that opens only into the middle ring, so an attacker can’t access them even if they get past the first line. No decorative towers, no open courtyards, no extra passages that could be exploited; every space serves a purpose. If you want to keep the fortress truly tight, you’ll need to enforce a strict patrol schedule and a system of watchtowers that look out directly over the moat. That’s the basic skeleton; we can flesh out the details later, but as long as we keep it compact and functional, the fortress will feel as if it were built to withstand a siege rather than an architectural whim.