Optimizing a nested loop with recursion

Hi,

I have the following code below that iterates all the possible combinations of a three state switch for three swithes. Using recursion I know this is possible to work with N number of switches but can't work out how to do it.
The code should loop though and give you 3^n combinations, if you can do this - using recursion or not, i don't mind - recursion was just the way I tried.

procedure TForm1.Button1Click(Sender: TObject);
Var
states,i,l,n,j,count,k : integer;
switch : array[0..2] of integer;
begin
  switch[0] := 0;
  switch[1] := 0;
  switch[2] := 0;

    For k := -1 to 1 do
    begin
      switch[2] := k;
      For l := -1 to 1 do
      begin
         switch[1] := l;
         For i := -1 to 1 do
         Begin
           switch[0] := i;
           memo1.lines.add(InttoStr(switch[0])+','+InttoStr(switch[1])+','+InttoStr(switch[2]))
        end;
      end;
  end;

end;



Thanks in advance. 125 points on offer.

Richard