Archive for the '-geometry' Category

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

May 28, 2018

9 November 1973, Germany

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

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.