Dragon Curve

A dragon curve is any member of a family of self-similar fractal curves, which can be approximated by recursive methods such as Lindenmayer systems as a procedure in Pascal shows:

procedure Dragon(n, a, t: Integer; d, x, y: Double; var b: TBitmap);
  var a1, a2: integer;
  begin
  if n <= 1 then begin
     with b.Canvas do begin
       Pen.Color := random(p);
       MoveTo(Trunc(x + 0.5), Trunc(y + 0.5));
       LineTo(Trunc(x + d * _cos[a] + 0.5), Trunc(y + d * _sin[a] + 0.5));
       exit;
     end;
   end;
   d := d * s;
   a1 := (a - t) and 7;
   a2 := (a + t) and 7;
  dragon(n - 1, a1, 1, d, x, y, b);
  dragon(n - 1, a2, -1, d, x + d * _cos[a1], y + d * _sin[a1], b);
end;

Recursively a right curling dragon is a right dragon followed by a left dragon, at 90-degree angle. And a left dragon is a left followed by a right. The same you get also with Python and Turtle in maXbox:

Const DRAGFUNC =
  'def dragon(level=4, size=200, direction=45):   '+LF+
  '  if level:                                     '+LF+
  '      right(direction)                          '+LF+
  '      dragon(level-1, size/1.41421356237, 45)   '+LF+
  '      left(direction * 2)                       '+LF+
  '      dragon(level-1, size/1.41421356237, -45)  '+LF+
  '      right(direction)                          '+LF+
  '  else:                                         '+LF+
  '      forward(size)                             ';

function PyCodeDragonTurtle(imgpath, aAPIKey: string): string;
begin
  with TPythonEngine.Create(Nil) do begin
  //pythonhome:= 'C:\Users\User\AppData\Local\Programs\Python\Python312\';
  try
    loadDLL;
    autofinalize:= false;
    ExecString('from turtle import right,left,forward,speed, exitonclick, hideturtle');
    ExecStr(DRAGFUNC); 
    ExecStr('speed(0)');  
    //ExecStr('hideturtle()'); 
    ExecStr('dragon(6)');
    ExecStr('exitonclick()');
    //result:= (EvalStr('r.json()')); *)
  except
    raiseError;        
  finally       
    Free;
  end; 
 end;
end; 

The dragon curve is probably most commonly thought of as the shape that is generated from repeatedly folding a strip of paper in half.

The script you get at:
Multilanguage Script

with Depth = 9