  Schubert polynomials for the classical groups were defined by S.Billey and
M.Haiman in 1995; they are polynomial representatives of Schubert classes in a
full flag variety of a classical group. We provide a combinatorial description
for these polynomials, as well as their double versions, by introducing
analogues of pipe dreams, or RC-graphs, for the Weyl groups of the classical
types.
