Porting a raylib example to GNU Algol 68

[Jose E. Marchesi]

Hi Mohammad.

I just tried the demo.  It works like a charm :)

>   int k_mouse_button_left = 0;
>   Color k_raywhite = (SHORTEN SHORTEN -11 {245},
>                       SHORTEN SHORTEN -11 {245},
>                       SHORTEN SHORTEN -11 {245},
>                       SHORTEN SHORTEN -1 {255}),
>         k_gray = (SHORTEN SHORTEN -126 {130},
>                   SHORTEN SHORTEN -126 {130},
>                   SHORTEN SHORTEN -126 {130},
>                   SHORTEN SHORTEN -1 {255}),
>         k_blue = (SHORTEN SHORTEN 0,
>                   SHORTEN SHORTEN 121,
>                   SHORTEN SHORTEN -15 {241},
>                   SHORTEN SHORTEN -1 {255}),
>         k_red = (SHORTEN SHORTEN -26 {230},
>                  SHORTEN SHORTEN 41,
>                  SHORTEN SHORTEN 55,
>                  SHORTEN SHORTEN -1 {255});

It seems to me, we may want to introduce an extension to allow a radix
10 for bits denotations, so in this sort of situation we could do:

    Color k_raywhite = (short short 10r245,
                        short short 10r245,
                        short short 10r245,
                        short short 10r255)