In single-step selection the entities selected or sorted, pebbles or whatever they are, are sorted once and for all. In cumulative selection, on the other hand, they ‘reproduce’; or in some other way the results of one sieving process are fed into a subsequent sieving, which is fed into …, and so on. The entities are subjected to selection or sorting over many ‘generations’ in succession. The end-product of one generation of selection is the starting point for the next generation of selection, and so on for many generations.
