state     sig_in = '0'          sig_in = '1'
          next_state, sig_out   next_state, sig_out
a         a, '1'                d, '0'
b         b, '0'                c, '1'
c         b, '0'                a, '1'
d         e, '1'                e, '0'
e         e, '0'                c, '0'