One Command Block

/summon Item ~ ~3 ~ {Riding:{Riding:{id:"FallingSand",Time:1,TileID:137,DropItem:0,TileEntityData:{Command:"/summon FallingSand ~ ~15 ~ {Time:1,TileID:72,Data:1,DropItem:0,Riding:{id:\"FallingSand\",TileID:137,Time:1,DropItem:0,TileEntityData:{Command:\"/setblock ~ ~1 ~ air\"},Riding:{id:\"FallingSand\",Time:1,TileID:137,DropItem:0,Motion:[0.9,0.9,0],TileEntityData:{Command:\"/summon Item ~ ~5 ~-1 {Riding:{Riding:{id:\\"FallingSand\\",Time:1,TileID:137,DropItem:0,TileEntityData:{Command:\\"/summon FallingSand ~ ~15 ~2 {TileID:1,Time:1,DropItem:0,Motion:[0.0,0.9,0.9]}\\"}},TileID:72,Time:1,DropItem:0,id:\\"FallingSand\\"},Item:{id:1,Damage:0,Count:1},Age:5979}\"}}}}"},DropItem:0},id:"FallingSand",Time:1,TileID:72,DropItem:0},Item:{id:1,Damage:0,Count:1},Age:5979}