The product group (Zm×Zn, +) contains subgroups H=<S> generated by zero or more elements. The left cosets and right cosets of H coincide because (Zm×Zn, +) is Abelian.
The cells of the array correspond to elements of . Click one or more cells to add elements to S; the elements of H=<S> are highlighted.
At any stage you may “freeze” the subgroup H under consideration and investigate its cosets. Once H is frozen, clicking a cell (a, b) highlights elements of the coset (a, b)+H in a different color.