/summon FallingSand ~ ~2 ~ {Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{Riding:{TileEntityData:{Command:"/fill ~2 ~-1 ~2 ~-2 ~4 ~14 minecraft:stained_glass 14 hollow",id:"Control"},id:"FallingSand",Block:"command_block",Time:1},TileEntityData:{Command:"/fill ~2 ~-2 ~2 ~-2 ~-2 ~14 minecraft:stained_hardened_clay 14",id:"Control"},id:"FallingSand",Block:"command_block