hwnd := ShowFrame(300, 200, 800, 600, 3, "red")
Sleep, 1000
WinClose, ahk_id %hwnd%
ExitApp

ShowFrame(x, y, w, h, thickness, color)  {
   static WS_EX_LAYERED := 0x80000, WS_EX_TRANSPARENT := 0x20
   
   Gui, New, % "+hwndhGui +ToolWindow -Caption +LastFound +AlwaysOnTop +Owner +E" . WS_EX_LAYERED | WS_EX_TRANSPARENT
   Gui, Color, %color%
   t := thickness, dx := w - t, dy := h - t
   WinSet, Region, % "0-0 " w "-0 " w "-" h " 0-" h " 0-0 " t "-" t " " dx "-" t " " dx "-" dy " " t "-" dy " " t "-" t
   WinSet, Transparent, 0xFF
   Gui, Show, NA x%x% y%y% w%w% h%h%
   Return hGui
}