I have yet to have the honor of encapsulating a twin placenta, and someday when one comes along, I will be sure to post my own pictures. Until then, here is a great resource with excellent pictures if you feel curious about seeing what a twin placenta looks like. http://pregnancy.about.com/od/pregnancy/ss/Twin-Placenta.htm.
There are great pictures of a twin placenta, the maternal side, the fetal side, how the umbilical cords are arranged, the amniotic sac, the layers of the amniotic sac: the chorion and amnion. It is pretty fascinating!