There is a big metallic cube in front of a small ball; what color is the cube?
return balls ;return #1 that  are small ;return cubes ;return #3 that  are big ;return #3 that  are metallic ;return #3 in both #4 and #5 ;return #6 that  are in front of a  #2 ;return the  color of #7
['select', 'filter', 'select', 'filter', 'filter', 'intersection', 'filter', 'project']