So, as we know, Madara unlocked his Rinnegan by "making" Hagoromo's Chakra; (Indra+Ashura). Now, Sasuke's Rinnegan is unique, well for it being in the actual eye socket... Lol Anyway, both Naruto and Sasuke acquired Hagoromo's power. Hagoromo was the one that gifted Sasuke with his Rinnegan but, the differance between Sasuke and Madara is that Madara's "Indra chakra" combined with the obtained "Ashura chakra" to create "Hagoromo Chakra"; the Rinnegan, whereas for Sasuke he already had "Indra Chakra" and added "Hagoromo Chakra" to the mix. Hagoromo's gifted him with the Rinnegan and Indra's added the Tomoes. It would kind of make sense, right? 
Well, probably bad, but what do you think?

Well, probably bad, but what do you think?