English: An animation of a Schrödinger cat state, a superposition of two harmonic oscillator states with a changing relative phase.

There are four stages in the animation: twisting the relative phase ${\displaystyle 0\to 2\pi \to 4\pi }$, rotating (backward time evolution) ${\displaystyle \pi /3\to 0}$, twisting the relative phase again ${\displaystyle 0\to 2\pi \to 4\pi }$, and finally rotating back (forward time evolution) ${\displaystyle 0\to \pi /3}$.

The bottom left 2D plot shows the Wigner function (aka. Wigner–Ville distribution), where the horizontal axis represents position and the vertical axis represents momentum. In the plot, green represents positive values and red represents negative values.

The top and right 1D plots show the corresponding marginal distributions of position and momentum, respectively. In these marginal plots, heights represent probability densities (${\displaystyle |\psi |^{2}}$), and colors represent the phases (${\displaystyle \arg \psi }$).