nether base (1.17)

summon falling_block ~ ~1 ~ {Time:1,BlockState:{Name:redstone_block},Passengers:[{id:armor_stand,Health:0,Passengers:[{id:falling_block,Time:1,BlockState:{Name:activator_rail},Passengers:[{id:command_block_minecart,Command:'/fill ~-2 ~-3 ~2 ~-10 ~4 ~10 minecraft:nether_bricks hollow'},{id:command_block_minecart,Command:'/fill ~-2 ~1 ~2 ~-10 ~1 ~10 minecraft:nether_bricks'},{id:command_block_minecart,Command:'/fill ~-3 ~2 ~2 ~-9 ~3 ~2 minecraft:red_stained_glass_pane'},{id:command_block_minecart,Command:'/fill ~-3 ~-1 ~2 ~-3 ~-2 ~2 minecraft:air'},{id:command_block_minecart,Command:'kill @e[type=minecraft:command_block_minecart]'}]}]}]}