/summon MinecartCommandBlock ~ ~2 ~ {Command:kill @e[type=MinecartCommandBlock,r=2],Riding:{id:MinecartCommandBlock,Command:summon FallingSand ~-1 ~ ~ {Block:redstone_block,Time:1,Riding:{id:FallingSand,Time:1,Block:command_block,TileEntityData:{Command:fill ~1 ~1 ~ ~ ~-2 ~ air}}},Riding:{id:MinecartCommandBlock,Command:setblock ~ ~-2 ~2 redstone_block,Riding:{id:MinecartCommandBlock,Command:setblock ~-1 ~-1 ~11 command_block 0 replace {Command:fill ~-1 ~-2 ~1 ~3 ~7 ~-11 air},Riding:{id:Minecart