"If a connected, planar graph is drawn on a plane then the plane can be divided into continuous regions called faces. A face is characterised by the cycle that forms its boundary."
This is what my book says, and then it goes on to illustrate an example by saying this graph:
... has 4 faces, namely A, B, C, D (D is the face bounded by the cycle (1,2,3,4,6,1)
however shouldn't there be at least 6 faces? ie a face bounded by (1,2,5,4,6,1) and (1,2,3,4,5,1)...?