for(int j = 0; j < N; j++) {
                if (i == 0)w_dl[i * N + j] = Wektor(-a/2, dl ,0);
                else if (i == 1)w_dl[i * N + j] = Wektor(dl, a/2, 0);
                else if (i == 2)w_dl[i * N + j] = Wektor(-dl,a/2, 0);
                else if (i == 3)w_dl[i * N + j] = Wektor(a / 2,-dl, 0);