Build a circular medieval tower with a TOTAL diameter betwee...

Build a circular medieval tower with a TOTAL diameter between 16 and 18 blocks maximum (from outer wall to outer wall). Do NOT exceed 18 blocks under any circumstance. The tower must be completely hollow inside, with no floors, pillars, stairs, ladders, or internal structures, as it is only meant to cover an XP farm. Use ONLY basic survival blocks, such as: cobblestone, stone, stone bricks, cracked stone bricks, mossy stone bricks, oak logs, spruce logs, oak planks, spruce planks, and slabs or stairs made from these materials. Do NOT use ores, decorative blocks, rare blocks, modded blocks, or creative-only blocks. Keep the design simple and functional, not decorative or oversized. Wall thickness should be 1 block only. The interior diameter must be approximately 14–16 blocks, leaving en