Perimeter Maker in One Command for 1.16

summon falling_block ~ ~2.5 ~ {BlockState:{Name:"minecraft:redstone_block"},Time:1,Passengers:[{id:"minecraft:falling_block",BlockState:{Name:"minecraft:activator_rail"},Time:1,Passengers:[{id:"minecraft:command_block_minecart",Command:"give @p bat_spawn_egg{display:{Name:'{\"text\":\"perimeter\"}'}}"},{id:"minecraft:command_block_minecart",Command:"scoreboard objectives add perimeterX dummy"},{id:"minecraft:command_block_minecart",Command:"scoreboard objectives add perimeterZ dummy"},{id:"minecraft:command_block_minecart",Command:"forceload add ~ ~ ~ ~"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~5 ~ repeating_command_block[facing=up]{auto:1b,Command:\"execute as @e[type=bat,name=perimeter] at @s run setblock ~ ~ ~ command_block[facing=up]{auto:0b,Command:\\\"scoreboard players set Perimeter perimeterX 8\\\"}\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~6 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute as @e[type=bat,name=perimeter] at @s run setblock ~ ~1 ~ chain_command_block[facing=up]{auto:1b,Command:\\\"scoreboard players set Perimeter perimeterZ 8\\\"}\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~7 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute as @e[type=bat,name=perimeter] at @s run setblock ~ ~2 ~ chain_command_block[facing=up]{auto:1b,Command:\\\"summon armor_stand ~ 0 ~ {CustomName:'{\\\\\\\"text\\\\\\\":\\\\\\\"perimeter\\\\\\\"}',NoGravity:1b,Marker:1b,Invisible:1b}\\\"}\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~8 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute as @e[type=bat,name=perimeter] at @s run setblock ~ ~3 ~ chain_command_block[facing=up]{auto:1b,Command:\\\"scoreboard players operation @e[type=armor_stand,name=perimeter] perimeterX = Perimeter perimeterX\\\"}\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~9 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute as @e[type=bat,name=perimeter] at @s run setblock ~ ~4 ~ chain_command_block[facing=up]{auto:1b,Command:\\\"fill ~ ~ ~ ~ ~-4 ~ air\\\"}\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~10 ~ chain_command_block[facing=up]{auto:1b,Command:\"kill @e[type=bat,name=perimeter]\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~11 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute as @e[type=armor_stand,name=perimeter,tag=!zLine] at @s run summon armor_stand ~ ~ ~ {CustomName:'{\\\"text\\\":\\\"zlineperimeter\\\"}',NoGravity:1b,Marker:1b,Invisible:1b,Tags:[\\\"zlinescore\\\"]}\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~12 ~ chain_command_block[facing=up]{auto:1b,Command:\"scoreboard players operation @e[type=armor_stand,name=zlineperimeter,tag=zlinescore] perimeterZ = Perimeter perimeterZ\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~13 ~ chain_command_block[facing=up]{auto:1b,Command:\"tag @e remove zlinescore\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~14 ~ chain_command_block[facing=up]{auto:1b,Command:\"tag @e[type=armor_stand,name=perimeter,tag=!zLine] add zLine\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~15 ~ chain_command_block[facing=up]{auto:1b,Command:\"kill @e[type=armor_stand,name=zlineperimeter,scores={perimeterZ=0}]\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~16 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute as @e[type=armor_stand,name=zlineperimeter] at @s run fill ~ ~5 ~ ~15 ~127 ~15 air\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~17 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute as @e[type=armor_stand,name=zlineperimeter] at @s run fill ~ ~128 ~ ~15 ~255 ~15 air\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~18 ~ chain_command_block[facing=up]{auto:1b,Command:\"scoreboard players remove @e[type=armor_stand,name=zlineperimeter] perimeterZ 1\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~19 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute as @e[type=armor_stand,name=zlineperimeter] at @s run tp @s ~ ~ ~16\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~20 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute unless entity @e[type=armor_stand,name=zlineperimeter] as @e[type=armor_stand,name=perimeter] at @s run tp @s ~16 ~ ~\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~21 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute unless entity @e[type=armor_stand,name=zlineperimeter] as @e[type=armor_stand,name=perimeter] at @s run scoreboard players remove @s perimeterX 1\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~22 ~ chain_command_block[facing=up]{auto:1b,Command:\"execute unless entity @e[type=armor_stand,name=zlineperimeter] as @e[type=armor_stand,name=perimeter] at @s run tag @s remove zLine\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~23 ~ chain_command_block[facing=up]{auto:1b,Command:\"kill @e[type=armor_stand,name=perimeter,scores={perimeterX=..0}]\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~2 ~ chain_command_block[facing=up]{auto:1b,Command:\"fill ~ ~ ~ ~ ~-4 ~ air\"}"},{id:"minecraft:command_block_minecart",Command:"setblock ~ ~1 ~ command_block[facing=up]{auto:1b,Command:\"kill @e[type=command_block_minecart,distance=..2]\"}"}]}]}