int
main()
{
        const char str[] = "1234567890+- abcdefghijklmnopqrstuvwxyz";
    int N=strlen(str);
        int i, j;

        for (i = 0; i < N; i++) {
        j=min(N-i, 16);
                write(2, str+i, j);
                j=min(16-j, N);
                write(2, str, j);
                puts("");
                sleep(1);
        }

        return 0;
}