circular arena for a minigame, 50 b...

circular arena for a minigame, 50 blocks diameter, one perfectly flat floor made of sand with a layer of tnt underneath, surrounded by a 6 block tall wall of stone bricks and mossy stone bricks with pillars every 8 blocks, floor is completely empty, decorations only on the outer wall, volcano theme with netherrack and magma blocks on the outside, symmetrical, no interior rooms