$ u_t = \Delta u + f(x,u), x \in \Omega $
under Dirichlet boundary condition on
$\partial \Omega$. Here
$\Omega$ is a two-dimensional open disk. We show that for any positive
integer $k$ there is a $C^k$ function $f$ such that the above equation
has a bounded solution whose $\omega$-limit set is
homeomorphic to
$S^1$. This shows that nonconvergent bounded solutions
can occur, in
contrast to one-dimensional equations, or higher-dimensional equations
with analytic nonlinearities, where bounded
solutions are always
convergent.