If at least one dog has its head tilted back looking straight up.
return dogs ;return head of #1 ;return #2 that is tilted back ;return #1 that has #3 ;return #4 that is looking straight up ;return number of  #5 ;return if  #5 is at least one
['select', 'project', 'filter', 'filter', 'filter', 'aggregate', 'boolean']