2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/89842We propose a simple numerical experiment of two slits interference of particles. It disproves the popular belief that such an interference is incompatible with a knowledge which slit each particle came through or, more generally, ``quantum particles could not have trajectories''. Our model is an illustration to the contextual interpretation of quantum probabilities.LaTeX2e, 12 pages, 4 PostScript figures, 1 program listingQuantum PhysicsMathematical Physics81-01, 81-04text