  The semi-classical study of the integer Quantum Hall conductivity is
investigated for electrons in a bi-periodic potential $V(x,y)$.
  The Hall conductivity is due to the tunnelling effect and we concentrate our
study to potentials having three wells in a periodic cell. A non-zero
topological conductivity requires special conditions for the positions, and
shapes of the wells. The results are derived analytically and well confirmed by
numerical calculations.
