  We study the pressure anisotropy in anisotropic finite-size systems in SU(3)
Yang-Mills theory at nonzero temperature. Lattice simulations are performed on
lattices with anisotropic spatial volumes with periodic boundary conditions.
The energy-momentum tensor defined through the gradient flow is used for the
analysis of the stress tensor on the lattice. We find that a clear finite-size
effect in the pressure anisotropy is observed only at a significantly shorter
spatial extent compared with the free scalar theory, even when accounting for a
rather large mass in the latter.
