  An elementary recursive model accounting for the quark spin in the
fragmentation of a quark into mesons is presented. The quark spin degree of
freedom is represented by a two-components spinor. Spin one meson can be
included. The model produces Collins effect and jet handedness. The influence
of the initial quark polarisation decays exponentially with the rank of the
meson, at dierent rates for longitudinal and transverse polarisations
