Many will think they may reasonably blame me by alleging that my proofs are opposed to the authority of certain men held in the highest reverence by … - Leonardo da Vinci

The air is filled with endless images of the objects distributed in it; and all are represented in all, and all in one, and all in each, whence it happens that if two mirrors are placed in such a manner as to face each other exactly, the first will be reflected in the second and the second in the first. The first being reflected in the second takes to it the image of itself with all the images represented in it, among which is the image of the second mirror, and so, image within image, they go on to infinity in such a manner as that each mirror has within it a mirror, each smaller than the last and one inside the other. Thus, by this example, it is clearly proved that every object sends its image to every spot whence the object itself can be seen; and the converse: That the same object may receive in itself all the images of the objects that are in front of it.

Perché la minestra si fredda.

Men do wrong to lament the flight of time, complaining that it passes too quickly and failing to perceive that its period is sufficiently long; but a good memory, with which nature has endowed us, causes everything that is long past to appear to us to be present.