Juubi eye origin.Also a bit of rinnengan:)
Well, one of the most important is the colour. This can also explain the rinnengan.Now, the creation of all things has a blue and red flame . Also, if the pic doesnt use, go 2 tis linkhttp://naruto.wikia.com/wiki/Sage_of_the_Six_Paths.
Take the the life part of the senju as blue, and the uchia as red(sharingan color) Combine blue+red which results in purple, which is also the color of the rinnengan. Also, this shows tht the juubi, due to its eye color, is both the uchiha and senju. This can be further evidenced by the fact tht it takes obito and madara(uchiha) to use hashi cell(senju) to control the juub. Also, here is my theory on the rinnengan. I believe tht the circles on the rinnengan actually symbol the rings of elemnt, fire-air-water-earth-lightning. So the rings on a rinnengan are proof tht the wielder can use the element, plus wiv the purple colour(senju+uchiha).
Now for the tricky part. . Or http://naruto.wikia.com/wiki/Byakugan. This here is the byakugan. Notice something, the gaps in them. Now, what ou can do is put some tomoes in this gap and colour it red and u hv the or http://naruto.wikia.com/wiki/Sharingan. Now, as previously, colour is impotant. White is a combination of all colour(ROYGBIV) so it is possible for the byakugan to see all the visible colour and have the vision they hv.
I know this is a lot but plz read this.
Now just one mre fact, the tomoe can also represent the man,earth and the sky. This is just pure cool.
Now, take all the above shit and incoporate i into the juubi dojutsu. Pretty badass huh