<p>The invention relates to a warped or curved surface (3) with an image visible from a reference point (1) which is not an element of the said surface (3), where the reference point (1) has fixed position with respect to the said surface (3), and the image on the said surface (3) is distorted in a way to provide an undistorted view (2) on the said image from the said reference point (1).</p>
