Evolution of the orbital-element distributions of theoretical stream associated with comet 12P/Pons-Brooks. The stream is modeled in the time of 12P-perihelion passage, which happened before 350 nominal orbital periods of the comet. The bottom-based curve in each plot illustrates the distribution in the time of modeling. The curves with the base shifted vertically up about an equidistant section show the behavior for another successive 500-year intervals. The top-based curve shows the distribution at the present.