  We examine here a scheme to generate a W state of an n-qubit system with
all-to-all pairwise exchange interaction between n qubits. This relies on
sharing of superposed excitations of a smaller number of $q$ qubits among
others. We present a bound on the maximal jumps from q to n and formalize a
scheme to generate $W_n$ state in $\mathcal{O}(\log_4 n)$ stages. We
demonstrate this scheme in the context of spin torque based quantum computing
architecture that are characterized by repeated interactions between static and
flying qubits.
