name: replace_b_by_bc
init: init 
accept: accept 

init, a
init, a, > 

init, B
init, B, > 

init, c
init, c, > 

init, b
insert_c, B, > 

init, _
clean, _, <

insert_c, a
move_a, c, > 

insert_c, b 
move_b, c, > 

insert_c, _
return, c, < 

move_a, a 
move_a, a, > 

move_a, b
move_b, a, > 

move_a, _ 
return, a, < 

move_b, a 
move_a, b, > 

move_b, b 
move_b, b, > 

move_b, _ 
return, b, < 

return, a
return, a, < 

return, b 
return, b, < 

return, c 
return, c, < 

return, B 
return, B, < 

return, _
init,   _, > 

clean, a
clean, a, < 

clean, B 
clean, b, < 

clean, c 
clean, c, < 

clean, _ 
accept, _, -