This example uses several forms. The first form has its FormStyle property set to fsMDIForm. The others have their FormStyle properties set to fsMDIChild and their Visible properties set to True. Add a main menu component and name one of the menu items MyCascade. This is code for the MyCascadeClick handler. When the user chooses the Cascade command, restored forms are arranged so that they overlap. Do not name the menu items "Cascade", as that will override the TForm method.
procedure TForm1.MyCascadeClick(Sender: TObject); begin Form1.Cascade; end;