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Madonna del cardellino by Raphael

The Madonna del cardellino or Madonna of the Goldfinch is a painting by the Italian renaissance artist Raphael, from c. 1505-1506. A 10-year restoration process was completed in 2008, after which the painting was returned to its home at the Uffizi in Florence.
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Uffizi Gallery**

The Uffizi Gallery is a museum in Florence, Italy. It is one of the oldest and most famous art museums of the Western world. Building of the palace was begun by Giorgio Vasari in 1560 for Cosimo I de' Medici as the offices for the Florentine magistrates. Source: Wikipedia, Uffizi.

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Golden rectangle**

A golden rectangle
is a rectangle whose side lengths are in the golden ratio,
one-to-phi, that is, approximately 1:1.618. A distinctive
feature of this shape is that when a square section is
removed, the remainder is another golden rectangle, that is,
with the same proportions as the first. Square removal can
be repeated infinitely, which leads to an approximation of
the golden or Fibonacci spiral.

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Droste Effect**

The Droste effect is a specific kind of recursive picture, one that in heraldry is termed mise en abyme. An image exhibiting the Droste effect depicts a smaller version of itself in a place where a similar picture would realistically be expected to appear. This smaller version then depicts an even smaller version of itself in the same place, and so on. Only in theory could this go on forever; practically, it continues only as long as the resolution of the picture allows, which is relatively short, since each iteration geometrically reduces the picture's size. It is a visual example of a strange loop, a self-referential system of instancing which is the cornerstone of fractal geometry.
Source:
Wikipedia,
Droste Effect.