  We continue our simulations of QCD with 2 flavours of colour-sextet quarks as
a model for walking technicolor. QCD with 3 flavours of colour-sextet quarks is
also studied for comparison with the 2-flavour theory. We simulate these
theories at finite temperatures T, using lattices with a finite extent $N_t
a=1/T$ in the (Euclidean) time direction. The lattice coupling at the
chiral-symmetry-restoration transition is measured as a function of $N_t$. If
this is indeed a finite-temperature transition, the evolution of this coupling
with $N_t$ as $N_t \rightarrow \infty$ and hence the lattice spacing $a
\rightarrow 0$ should be described by asymptotic freedom. If so, the theory is
QCD-like and walking. If, however, this coupling approaches a constant non-zero
value in the large $N_t$ limit, the transition is a bulk transition and the
continuum theory is conformal. For the 2-flavour theory, the coupling does show
a significant decrease between $N_t=8$ and $N_t=12$, favouring the walking
scenario. However, preliminary results are that the change is less than that
predicted by asymptotic freedom. For the 3-flavour case, which is expected to
be conformal, there is still a significant decrease in the coupling between
$N_t=6$ and $N_t=8$, indicating that we are not yet at large enough $N_t$.
