// *** before: ***
uses
  Forms, StdCtrls, Graphics;

// the only interface library was the VCL, a wrapper around Windows
// window handles. The same form could not be built for another system

// *** in version XE2: ***
uses
  FMX.Forms, FMX.Objects, FMX.Types;

// FireMonkey draws its controls itself, so one form builds for Windows
// and for macOS (later releases added iOS and Android)
type
  TMainForm = class(TForm)
    Circle1: TCircle;
    procedure FormCreate(Sender: TObject);
  end;

procedure TMainForm.FormCreate(Sender: TObject);
begin
  Circle1.Fill.Color := TAlphaColorRec.Crimson;
  Circle1.RotationAngle := 30;   // every control is a drawn shape, so it
  Circle1.Opacity := 0.5;        // can be rotated and made transparent
end;