Seamless/Smooth Blocks (Minecraft 1.12.2 (Bukkit))

/summon falling_block ~ ~2 ~ {Block:stone,Time:1,Passengers:[{id:falling_block,Time:1,Block:redstone_block,Passengers:[{id:falling_block,Time:1,Block:activator_rail,Passengers:[{id:commandblock_minecart,Command:"fill ~2 ~-1 ~-2 ~7 ~-1 ~2 stained_glass 8"},{id:commandblock_minecart,Command:"fill ~3 ~-1 ~-1 ~6 ~-1 ~1 air"},{id:commandblock_minecart,Command:"fill ~2 ~-2 ~-2 ~7 ~-2 ~2 concrete 7"},{id:commandblock_minecart,Command:"fill ~2 ~ ~-2 ~7 ~ ~2 concrete 7"},{id:commandblock_minecart,Command:"setblock ~6 ~-1 ~-1 repeating_command_block 4 replace {auto:1b,Command:\"execute @e[tag=SSSlab,type=chicken] ~ ~ ~ setblock ~ ~ ~ double_stone_slab 8\"}"},{id:commandblock_minecart,Command:"setblock ~6 ~-1 ~ repeating_command_block 4 replace {auto:1b,Command:\"execute @e[tag=SSandstoneSlab,type=chicken] ~ ~ ~ setblock ~ ~ ~ double_stone_slab 9\"}"},{id:commandblock_minecart,Command:"setblock ~6 ~-1 ~1 repeating_command_block 4 replace {auto:1b,Command:\"execute @e[tag=SRSandstoneSlab,type=chicken] ~ ~ ~ setblock ~ ~ ~ double_stone_slab2 9\"}"},{id:commandblock_minecart,Command:"setblock ~5 ~-1 ~1 chain_command_block 4 replace {auto:1b,Command:\"minecraft:tp @e[tag=SRSandstoneSlab,type=chicken] ~ ~-1000 ~\"}"},{id:commandblock_minecart,Command:"setblock ~5 ~-1 ~ chain_command_block 4 replace {auto:1b,Command:\"minecraft:tp @e[tag=SSandstoneSlab,type=chicken] ~ ~-1000 ~\"}"},{id:commandblock_minecart,Command:"setblock ~5 ~-1 ~-1 chain_command_block 4 replace {auto:1b,Command:\"minecraft:tp @e[tag=SSSlab,type=chicken] ~ ~-1000 ~\"}"},{id:commandblock_minecart,Command:"fill ~4 ~-1 ~-1 ~4 ~-1 ~1 wool 7"},{id:commandblock_minecart,Command:"setblock ~3 ~-1 ~-1 double_stone_slab 8"},{id:commandblock_minecart,Command:"setblock ~3 ~-1 ~ double_stone_slab 9"},{id:commandblock_minecart,Command:"setblock ~3 ~-1 ~1 double_stone_slab2 9"},{id:commandblock_minecart,Command:"setblock ~1 ~-1 ~-1 wall_sign 4 replace {Text1:\"{\\\"text\\\":\\\"\\\",\\\"clickEvent\\\":{\\\"action\\\":\\\"run_command\\\",\\\"value\\\":\\\"minecraft:give @s spawn_egg 64 0 {EntityTag:{id:chicken,Tags:[\\\\\\\"SSSlab\\\\\\\"]},display:{LocName:\\\\\\\"\\\\u00a77Seamless Double Stone Slab\\\\\\\"}}\\\"}}\",Text2:\"{\\\"text\\\":\\\"Click To Get\\\",\\\"color\\\":\\\"green\\\",\\\"clickEvent\\\":{\\\"action\\\":\\\"run_command\\\",\\\"value\\\":\\\"minecraft:give @s spawn_egg 64 0 {EntityTag:{id:chicken,Tags:[\\\\\\\"SSandstoneSlab\\\\\\\"]},display:{LocName:\\\\\\\"\\\\u00a7eSmooth Double Sandstone Slab\\\\\\\"}}\\\"}}\",Text3:\"{\\\"text\\\":\\\"Items.\\\",\\\"color\\\":\\\"green\\\",\\\"clickEvent\\\":{\\\"action\\\":\\\"run_command\\\",\\\"value\\\":\\\"minecraft:give @s spawn_egg 64 0 {EntityTag:{id:chicken,Tags:[\\\\\\\"SRSandstoneSlab\\\\\\\"]},display:{LocName:\\\\\\\"\\\\u00a7cSmooth Double Red Sandstone Slab\\\\\\\"}}\\\"}}\"}"},{id:commandblock_minecart,Command:"setblock ~1 ~-1 ~1 wall_sign 4 replace {Text1:\"{\\\"text\\\":\\\"\\\"}\",Text2:\"{\\\"text\\\":\\\"Click To\\\",\\\"color\\\":\\\"dark_red\\\"}\",Text3:\"{\\\"text\\\":\\\"Destroy.\\\",\\\"color\\\":\\\"dark_red\\\",\\\"clickEvent\\\":{\\\"action\\\":\\\"run_command\\\",\\\"value\\\":\\\"minecraft:fill ~ ~-1 ~1 ~6 ~1 ~-3 air\\\"}}\"}"},{id:commandblock_minecart,Command:"tellraw @a [\"\",{\"text\":\"Seamless/Smooth Blocks\",\"color\":\"gold\"},{\"text\":\"\\nAll in one command.\",\"color\":\"gold\"},{\"text\":\"\\n- CMDProGamer\",\"color\":\"dark_red\"}]"},{id:commandblock_minecart,Command:"setblock ~1 ~-1 ~ command_block 0 replace {auto:1b,Command:\"minecraft:fill ~-2 ~-2 ~ ~ ~1 ~ air\"}"},{id:commandblock_minecart,Command:"minecraft:kill @e[type=commandblock_minecart,r=1]"}]}]}]}