一時的な座標でいいなら描画後の保護とか気にしない前提ならWIN32APIをUWSCから叩けばいいからなぁ
Procedure Rectan(inXYWH, inWidth=2, inColor=$0000FF)
　DEF_DLL GetDC(Hwnd):long:user32
　DEF_DLL ReleaseDC(Hwnd, Long):long:user32
　DEF_DLL SelectObject(long, long):long:gdi32
　DEF_DLL Rectangle(long, long, long, long, long):long:gdi32
　DEF_DLL CreatePen(long, long, long):long:gdi32
　DEF_DLL GetStockObject(long):long:gdi32
　DEF_DLL DeleteObject(long):long:gdi32
　DEF_DLL InvalidateRect(dword, dword, bool):bool:user32
　CONST PS_SOLID = 0
　CONST NULL_BRUSH = 5
　tmpXYWH = Split(inXYWH, ",", True, True)
　If Length(tmpXYWH) <> 4 Then
　　//消去
　　InvalidateRect(NULL, NULL, TRUE)
　　Exit
　EndIf
　x1 = tmpXYWH[0]
　y1 = tmpXYWH[1]
　x2 = x1 + tmpXYWH[2]
　y2 = y1 + tmpXYWH[3]
　dc = GetDC(0)
　pen = CreatePen(PS_SOLID, inWidth, inColor)
　SelectObject(dc, pen)
　SelectObject(dc, GetStockObject(NULL_BRUSH))
　Rectangle(dc, x1, y1, x2, y2)
　DeleteObject(pen)
　ReleaseDC(0, dc)
Fend