A circular, minimalist hub for a Mi...

A circular, minimalist hub for a Minecraft parkour map, built in a single block type of your choice (full creative freedom on material, texture and style — surprise me, but keep it clean and understated, no unnecessary ornamentation). Round structure when viewed from above, hollow and empty interior (no furniture, no interior decoration, just walls, floor, and either a ceiling or an open skylight). Multiple stacked floors/levels connected by a central opening, like an atrium. The space should be large and tall enough to later hold several distinct sections along the walls (roughly 4 to 6), and to place pressure plates and buttons on the floor without feeling cramped. Elegant, airy design, not overloaded — meant to feel like a central lobby people want to linger in.