Squaring the circle. 17th-century diagram showing geometrical calculations related to the problem known as 'squaring the circle'. Also known as 'quadrature of the circle', this problem involves the attempt to construct a square of the same area as a given circle using a finite number of manipulations. In 1882, it was shown that this task was impossible due to the transcendental nature of the number 'pi' (the ratio of a circle's circumference and its diameter). This diagram is from 'Quadratura circuli nova' (New quadrature of the circle, 1608) by Thomas Brugmann.