/summon minecraft:falling_block ~ ~13 ~ {Time:1,Block:command_block,TileEntityData:{auto:1b,Command:summon minecraft:falling_block ~3 ~ ~-1 {Block:planks,Time:1,Passengers:[{id:"falling_block",Block:planks,Time:1,Passengers:[{id:"falling_block",Time:1,Block:nether_brick_stairs,Data:1}]}]}},Passengers:[{id:"falling_block",Time:1,Block:command_block,TileEntityData:{auto:1,Command:summon minecraft:falling_block ~3 ~ ~ {Block:planks,Time:1,Passengers:[{id:"falling_block",Block:planks,Time:1,Passengers:[{id:"falling_block",Time:1,Block:nether_brick_stairs,Data:1}]}]}},Passengers:[{id:"falling_block",Block:command_block,Time:1,TileEntityData:{auto:1,Command:summon minecraft:falling_block ~3 ~ ~1 {Block:planks,Time:1,Passengers:[{id:"falling_block",Block:planks,Time:1,Passengers:[{id:"falling_block",Time:1,Block:nether_brick_stairs,Data:1}]}]}},Passengers:[{id:"falling_block",Block:command_block,Time:1,TileEntityData:{auto:1,Command:summon minecraft:falling_block ~2 ~ ~-1 {Block:planks,Time:1,Passengers:[{id:"falling_block",Block:planks,Time:1,Passengers:[{id:"falling_block",Time:1,Block:nether_brick_stairs,Data:2}]}]}},Passengers:[{id:"falling_block",Time:1,Block:command_block,TileEntityData:{auto:1,Command:summon minecraft:falling_block ~2 ~ ~ {Block:barrier,Time:1,Passengers:[{id:"falling_block",Block:planks,Time:1,Passengers:[{id:"falling_block",Time:1,Block:nether_brick}]}]}},Passengers:[{id:"falling_block",Time:1,Block:command_block,TileEntityData:{auto:1,Command:summon minecraft:falling_block ~2 ~ ~1 {Block:planks,Time:1,Passengers:[{id:"falling_block",Block:planks,Time:1,Passengers:[{id:"falling_block",Time:1,Block:nether_brick_stairs,Data:3}]}]}},Passengers:[{id:"falling_block",Time:1,Block:command_block,TileEntityData:{auto:1,Command:summon minecraft:falling_block ~1 ~ ~-1 {Block:planks,Time:1,Passengers:[{id:"falling_block",Block:planks,Time:1,Passengers:[{id:"falling_block",Time:1,Block:nether_brick_stairs,Data:0}]}]}},Passengers:[{id:"falling_block",Time:1,Block:command_block,TileEntityData:{auto:1,Command:summon minecraft:falling_block ~1 ~ ~ {Block:barrier,Time:1,Passengers:[{id:"falling_block",Block:planks,Time:1,Passengers:[{id:"falling_block",Time:1,Block:nether_brick_stairs,Data:0}]}]}},Passengers:[{id:"falling_block",Time:1,Block:command_block,TileEntityData:{auto:1,Command:summon minecraft:falling_block ~1 ~ ~1 {Block:planks,Time:1,Passengers:[{id:"falling_block",Block:planks,Time:1,Passengers:[{id:"falling_block",Time:1,Block:nether_brick_stairs,Data:0}]}]}},Passengers:[{id:"falling_block",Time:1,Block:command_block,TileEntityData:{auto:1,Command:fill ~ ~ ~ ~ ~-10 ~ minecraft:air}}]}]}]}]}]}]}]}]}]}