Is the thing between the two big things the same shape as the as yet unmentioned thing?
return things ;return #1 that are big ;return the  thing  between the   two of #2 ;return #1 besides  #2 ,  #3 ;return shape of #3 ;return shape of #4 ;return if #5 is the  same as #6
['select', 'filter', 'project', 'filter', 'project', 'project', 'boolean']