Posts Tagged ‘幾何学切手’

icosahedron and Euler’s formula / 正二十面体とオイラーの多面体公式

September 19, 2018

6 September 1983, German Democratic Republic
Death Bicentenary of Leonhard Euler
design: A. Bengs

The out-line geometry is Icosahedron and the formula is thought by Euler on the right.  The formula is “v (vertices) – e (edges) + f (faces) = 2” in English.  Some people think this is very beautiful formula – well, for me as non-mathematician, polyhedra as three-dimensional objects are more attractive.

左に描かれている立体は正二十面体で、真ん中に「オイラーの多面体公式」があり、右がそのオイラー本人です。この公式は、( 頂点の数 )- (辺の数 )+ (面の数) = 2 というもので「世界で二番目に美しい数式」という本が上梓されていますが、、、数学者ではないわたしにとっては、立体の多面体のほうがよほど魅力的に映ります。

Impossible object 3 / 不可能図形 3

August 22, 2018

16 February 1982, Sweden
“Impossible Object”
designer: Oscar Reutersvärd
engraver: Czesław Słania

The third stamp designed by Oscar Reutersvärd.  This one is also, is not possible to exist in the three-dimensional world.  A visual trick of perspective in a subtle and somehow gentle way – I like it!


floating Cube / 宙に浮く立方体(正六面体)

July 5, 2018

10 November 1970, Netherlands
“Children’s Stamp”
design: William Graatsma & Jan Slothouber

Slothouber and Graatsma were a design/architectural unit which formed the Centre for Cubic Constructions (CCC) in Heerlen and made a Dutch presentation at the Venice Biennial in 1970.  Their creations were always related to cubes – thus their retrospective exhibition was named Cubics.  More images from the show and the set of stamps are shown in this link.

One of my best favourite stamps of all time and I wonder why I have not featured it in this blog until now!



Cube (hexahedron) on a mountain / 山の上の正六面体

July 1, 2018

1978, Luxembourg
175th Anniversary of Grand Lodge
designer: Raymon Mehlen / engraver: Wolfgang Seidel

A huuuuge Cube/regular hexahedron is sitting on top of a mountain… It seems that this stamp is celebrating the anniversary of Freemasonry and I only guess that the Cube has some iconic meaning to them.  Ornamental typography is in similar style to this book cover, says ‘Pioneer of graphic art’.


great stellated dodecahedron or? / 大星型十二面体それとも?

May 28, 2018

9 November 1973, Germany
design: I. Monson-Baumgart

One more stamp from the same Christmas season, which I had already posted in 2011.  At that time I just thought it is a beautiful stamp – now I notice that this looks very much alike to a Great stellated dodecahedron.  But it is another 2D illusion and still I love it – crisp intaglio print with 70’s colours.


stellated dodecahedron or? / 小星型十二面体それとも?

May 14, 2018

9 November 1973, Germany-Berlin
design: I. Monson-Baumgart

My head is traveling in the world of polyhedra these days – this is one of the reasons why I did not update this blog.  Now, as I found several polyhedral postal stamps I am very keen to introduce them to my audience.

When I saw this stamp, I thought “Wow! is this a stellated dodecahedron? – so cool!!”  Then I realised that the stamp designer did not make proper research.  Well, there was no google search in 1973, and not many geometry or maths books carried a correct image of it.  This could be a Small stellated Dodecahedron – but, they are made with pentagonal pyramids and not hexagonal.  If you look at this stamp closely, you will notice that this is a 2D illusion and not an existing polyhedron.  How did the German authorities let this incorrect depiction get past?  Well – this was for Christmas, and I love it still.