A particle in a hard rectangular box has standing-wave energy eigenstates. Superpositions of several eigenstates make the density breathe, shear, and form moving nodal lines.

Bohmian particles are advanced by the probability current. They do not push the wave around; the wave guides them. The Pauli option adds a spin-current term, using the same 2D form as the tunneling demo.

Use a non-Born initial particle distribution to watch the particle cloud stretch and fold under a time-dependent wave. Born-rule seeding starts in quantum equilibrium.

The ground state is included as a stationary reference. The superposition presets mix x and y quantum numbers so the trajectories are genuinely two-dimensional.