Please see figures at https://www.pks.mpg.de/de/nonlinear-dynamics-and-time-series-analysis/visualization-of-dynamical-systems/poincare-recurrences.
I heard that one of the applications of the Poincare recurrence theorem (which I do not state here, see http://en.wikipedia.org/wiki/Poincar%C3%A9_recurrence_theorem) is to explain that the original image reappear in the Baker's map, but I do not understand how this follows.
The Baker's map is a certain map defined on the square, and Poincare recurrence theorem applied to this map just gives us that each individual point returns, under high iterates of the map, arbitrarily close to its original location, but this does not explain that the image as a whole "returns" to itself.