The desymmetrized PSL(2,Z) group is considered. The congruence subgroups of the desymmetrized PSL(2,Z) group are analysed according to the hyperbolic reflections contained. The Laplace-Beltrami problem and the Hamiltonian problem associated with the Laplace-Beltrami operator are discussed according to the boundary conditions for the grouppal structures. New constructions of the leaky tori are found; in particular, they are obtained after the generators of the PSL(2,Z) group, from the desymmetrized-triangle PSL(2,Z) group, and from the ’square-box’ Γ0 congruence subgroup of the desymmetrized PSL(2,Z) group