We have branch A, branch B, and branch C.
Currently I'm on branch C.
               A1 ----- A2
              /
             /  B1 -------- B2
            /  /
- M1 ----- M2 ------ M3 ---------------
            \
             C1 ---- C2
                      ^HEAD
Is it possible to merge branch A into branch B without leaving branch C?
 
     
    