If one of the railings has white main posts with smaller black posts in between.
return railings ;return posts of #1 ;return #2 that is main ;return #3 that is white ;return #2 that are black ;return #5 that are smaller ;return #4 that are with #6 in  between ;return #1 that has #7 ;return number of  #8 ;return if  #9 is equal to  one
['select', 'project', 'filter', 'filter', 'filter', 'filter', 'filter', 'filter', 'aggregate', 'boolean']