Source: http://www.flickr.com. Uploaded and tagged with “churchwarddesign” by “Karen Horton” on Flickr. License: Creative Commons Attribution Non-commercial.
c. 1973, Europa CEPT issue
The design that year, a stylised post horn, was made by the Norwegian artist Leif Frimann Anisdahl (24 countries; 50 stamps). The 3 arrows are said to represent CEPT’s primary objectives: post, telegraph and telephone services — Europa-Stamps blog
Note that the umlaut in Fürstentum [Principality] has been replaced with UE. Even if the character set of Churchward Design were lacking umlauts, it would have been easy for the designer to add a pair of dots. I assume this was done to get a compact and even block of all-caps, with no protruding bits.