What is the shape of the gray metallic object in front of the two metallic cube objects?
return cubes ;return #1 that  are metallic  ;return objects ;return #3 that  are gray ;return #4 that  are metallic  ;return #5 that  are in front of #2 ;return shape of #6
['select', 'filter', 'select', 'filter', 'filter', 'filter', 'project']