two spheres are hidden by the large blue metallic cube, one is purple, what color is the other?
return cube ;return #1 that is  large ;return #2 that is  blue ;return #3 that is  metallic ;return spheres ;return #5 that are hidden by #4 ;return colors of #6 ;return #7 besides  purple
['select', 'filter', 'filter', 'filter', 'select', 'filter', 'project', 'discard']