Non-cyclic permutations

program Project1;
{$APPTYPE CONSOLE}
uses
  System.SysUtils;
type
  Tset = set of char;

procedure Perm( prefix : string; Set2 : Tset);
begin
    if Set2 = []  then   writeln(prefix)
                  else   for var s in Set2 do begin
                             var Set3 := Set2 - [s];
                             Perm(prefix+s, Set3)
                         end;
end;

var Set1 :Tset;

begin
        Set1 := ['1','2','3','4'];
    var Set2 := Set1 - ['1'];
    Perm( '1', Set2);

    readln;
end.