File:Двоичное дерево.png

uses GraphABC; 
const
  Angle = -Pi / 4;

type
  EdgeData = auto class
    A, B, C: Point;
    R: integer;
  end;

var
  DataStack: Stack<EdgeData>;

function RotatePoint(pA: Point; r, angle: integer): Point;
begin
  var angle2 := DegToRad(angle);
  Result := new Point(Round(pA.X + r * Cos(angle2)), Round(pA.Y + r * Sin(angle2)));
end;

procedure PushTreePart(pB: Point; r: integer):=DataStack.Push(new EdgeData(RotatePoint(pB, r, -135), pB, RotatePoint(pB, r, -45), r));

function RIsBig(dt: EdgeData):= dt.R > 5;

begin
  LockDrawing();
  
  DataStack := new Stack<EdgeData>();
  
  PushTreePart(new Point(300, 300), 200);
  while DataStack.Count > 0 do
  begin
    var dt := DataStack.Pop();
    
    var pD := new Point((dt.A.X + dt.C.X) div 2, (dt.A.Y + dt.C.Y) div 2);
    Line(dt.A.X, dt.A.Y, dt.C.X, dt.C.Y);
    Line(pD.X, pD.Y, dt.B.X, dt.B.Y);
    
    if RIsBig(dt) then
    begin
      var r2 := dt.R div 2;
      PushTreePart(dt.A, r2);
      PushTreePart(dt.C, r2);
    end;
  end;
  Redraw();
end.