  In this paper we construct examples of commuting ordinary scalar differential
operators with polynomial coefficients that are related to a spectral curve of
an arbitrary genus g>0 and to an arbitrary rank r>1 of the vector bundle of
common eigenfunctions of the commuting operators over the spectral curve. This
solves completely the well-known existence problem for commuting operators of
arbitrary genus and arbitrary rank with polynomial coefficients. The
constructed commuting operators of arbitrary rank r>1 and arbitrary genus g>0
are given explicitly, they are generated by the Chebyshev polynomials T_r (x).
