A particle model developed elsewhere is presented very briefly, in which particles are seen as vortex structures in a kind of fluid. The particle core is tied by vortex lines to the core of other particles in the vicinity. The model is shown to explain spin ½ as a topological effect. It also sheds some light on the process of intrication. But vortex lines also induce velocities on themselves and on other vortex lines. When the Hasimoto transformation is used, the velocity induction equation is shown to give rise to the Schrödinger equation for the particle. We also consider the multi-particle systems and we give a tentative explanation for the Pauli exclusion principle. A particle model developed elsewhere is presented very briefly, in which particles are seen as vortex structures in a kind of fluid. The particle core is tied by vortex lines to the core of other particles in the vicinity. The model is shown to explain spin ½ as a topological effect. It also sheds some light on the process of intrication. But vortex lines also induce velocities on themselves and on other vortex lines. When the Hasimoto transformation is used, the velocity induction equation is shown to give rise to the Schrödinger equation for the particle. We also consider the multi-particle systems and we give a tentative explanation for the Pauli exclusion principle.