We show that
h
(
f
∞
)
=
log
2
h({f_\infty }) = \log 2
where
f
∞
{f_\infty }
is the map on the space of sequences of zeros and ones induced by the block map
f
(
x
0
,
…
,
x
k
)
=
x
0
+
Π
i
=
1
k
(
x
i
+
b
i
)
f({x_0}, \ldots ,{x_k}) = {x_0} + \Pi _{i = 1}^k({x_i} + {b_i})
where
k
⩾
2
k \geqslant 2
and the k-block
b
1
…
b
k
{b_1} \ldots {b_k}
is aperiodic.