Nothing too complex about this tooth when viewed straight on...
The complexity of the distal can only begin to be apprecaited from an angled radiograph.
3 distinct canal orifices can be seen entering the distal root (left side of photo). Note the ovoid shaped ML canal (seen in the upper right). The elliptical form of this canal is actually the result of a anastamosis of two canals, a middle mesial canal with the ML canal. Many would call this a five canal molar but in my opinion it would not be too much of a stretch to call it a a six canal molar.
Note the 5 distinct portals of exit in this case.