与此同时，在Maurits Cornelis Escher的生活中
完整生平1954
An exhibition for the Mathematical Congress
In 1954, for the International Congress of Mathematicians in Amsterdam, an exhibition of Escher’s work organised by N. G. de Bruijn opened at the Stedelijk Museum; Roger Penrose and H. S. M. Coxeter were deeply impressed by his intuitive grasp of mathematics. The exhibition took up so much time that in 1954 Escher made only two works.
27 April 1955
Knight of the Order of Orange-Nassau
On 27 April 1955 Escher was made a Knight (fifth class) of the Order of Orange-Nassau; in 1967 Queen Juliana raised him to the rank of Officer.
1956–1960
The Penroses and “impossible figures”
“House of Stairs” (1951) attracted the interest of the mathematician Roger Penrose and his father, the biologist Lionel Penrose; in 1956 they published a paper on impossible objects and later sent Escher a copy. He replied, admiring their continuously rising flights of steps, and enclosed a print of “Ascending and Descending” (1960); he went on to use the Penrose triangle repeatedly, notably in “Waterfall” (1961).
![Ginevra de' Benci [obverse], Leonardo da Vinci, c. 1474/1478](https://api.nga.gov/iiif/8f29e3c9-a289-4d53-abf0-31a66e9e98fa/full/!2400,2400/0/default.jpg)
![Wreath of Laurel, Palm, and Juniper with a Scroll inscribed Virtutem Forma Decorat [reverse], Leonardo da Vinci, c. 1474/1478](https://api.nga.gov/iiif/ff62e8d0-45c4-498f-ad36-6358de827e04/full/!2400,2400/0/default.jpg)
