name: copy to lower 
init: q
accept: accept

q, x, _
q, _, x, >, > 

q, y, _
q'', _, z, >, > 

q'', x, _
q  , x, y, -, > 

q'', y, _
q  , y, y, -, > 

q'', _, _
accept, _, _, -, - 

q, _, _
accept, _, _, -, -