move, y <=> x, move
move, x, x <=> x, x, eval
move, x <=> x

odd, y <=> x, x, x, x, x, x, odd
odd <=> x, eval

eval, x, x <=> y, eval
eval, x <=> x, x, x, odd
eval <=> move

start <=>
  x, x, x, x, x,
  x, x, x, x, x,
  x, x, eval