Reducing entropy in a randomly half-filled 5x5x5 lattice of atoms. Each row shows a snapshot of the 5 planes in the lattice. The top row shows the initial random distribution of atoms among the 3D array of 125 possible sites. The second row show the distributions of atoms after the first sort and the third row shows the distribution after the second sort, at which point the target 5x5x2 sublattice is completely filled. This process reduces the entropy in the system by a factor of about 2.4.