The sweeper problem says that given a closed area inside an infinite grid, some mass (trash) inside the area and a sweeper person that cleans a tile every time they pass over it (moving the mass to neighbours tiles with a given fixed distribution, i.e. the same amount of thrash to every neightbour) then once the trash is completely taken out of the area the distribution of the trash will be the same no matter how the area was sweep.
This is an interactive demo where you can check that the theorem just stated holds experimentally (a formal proof of the theorem is found here, but it is in Spanish).
Copyright (c) 2022 Zubieta Rico, Jose Joaquin and Guevara Díaz, Karlo Jair.