See N Smell

On Page One Fifty Five,  Sayadaw explains that having seen the first four elements in these tiny particles, one can also then see the second four, and on this page, we have color (the object of sight that is found in all rupa-kalapas) and odor (which it is noted is highly dependent on the nose sense and the nose is necessary to discern the properties, even though the mind-door is happening at the same time).