  Recently Ott, Tomforde and Willis proposed a new approach for one sided shift
spaces over infinite alphabets. In this new approach the conjugacy classes of
shifts of finite type, edge shifts, and M-step shifts are distinct and the
authors conjecture that for each non-negative integer M there exist an
(M+1)-step shift space that is not conjugate to any M-step shift. In this short
paper we build a class of (M+1)-step shifts that are not conjugate to any
M-step shift and hence show that their conjecture is correct.
