There are two absolutely identical pattern, for example, two equal black squares. Seeing them in the stereoscope, we will see one square, no different from each of the two separately. If in the center of each square has a white dot, and it is, of course, will be in the square that is visible in the stereoscope. But is this point on the same square a bit to move away from the center, so that was quite an unexpected effect: the stereoscope will still be visible one point, but not at the field square and in front of or behind him. Quite negligible difference in both paintings to call using the stereoscope impression of depth.
This gives a simple way to detect counterfeit Bank notes and documents. Is placed in a stereoscope suspect banknotes near authentic, to detect a fake, like a skilful it was: a tiny difference of water to the letter, in one stroke will immediately catch the eye, as this letter or stroke will appear in front of or behind the rest of the background [the Idea, first expressed in the mid-nineteenth century Trust, may not be applicable to all of the cash signs of our time. Technical conditions of their printing such that the resulting proofs not given in the stereoscope impression of a flat image, even if both banknote is genuine. But the reception of the Species is quite suitable to differentiate between the two impressions of the same book set from the print made with the newly typed font.].