gistfile1.pas

    h := 1;                                 // Shell-Sort
    repeat
        h := 3 * h + 1;
    until h > LBoxDemo.Items.Count - 1;

    repeat
        h := h div 3;
        for i := h to (LBoxDemo.Items.Count - 1) do
        begin
            str := LBoxDemo.Items[i];
            j := i;
            while ((j >= h) and (LBoxDemo.Items[j-h] > str)) do
            begin
                LBoxDemo.Items[j] := LBoxDemo.Items[j-h];
                j := j - h;
            end;
            LBoxDemo.Items[j] := str;
        end;
    until h <= 1;