The smaller portion of blocks in a split will always be removed. If the blocks are in a line, then
cutting close to what would constitute the middle will remove everything. In certain instances, it
may be beneficial to separate blocks which respawn in a puzzle. To do this, remove a block which 
will remove the lesser portion, or remove an end block: 

  ##X###
  XXX###

Move the visible portion: 
  XXX--->###

Let the blocks respawn: 
  ###  ###