expression         address        value
----------         -------        -----
m.ch               0xbb00         'f'

m.next             0xbb02         0xa004 (reference to the 'd' node)

m.next.next        0xa006         0xff00 (reference to the 'e' node)

n.next             0xbe02         0x3004 (reference to the 'c' node)

n.next.ch          0x3004         'c'

n.next.next.next   0xbb02         0xa004 (reference to the 'd' node)