I'm not going to sign myself up for the full #30daymapchallenge this year. But since the postcode map of Germany I made last year appeared to be popular (https://en.osm.town/@koriander/113415136113482153), I decided to follow up with a version for Austria, which interestingly doesn't make use of a leading zero in their four digit postcodes. I'm inclined to make some more of these, so feel free to ask for specific regions.
@koriander this looks really striking. Great idea. Would love to see one for the UK but not sure how well our postcodes suit this format.
@Shobeck I looked into this, but the alphanumerical codes seem to rarely feature the attribute 'consecutive'. I know France is not what you asked for, but a shapefile was easy to come by. It illustrates what happens when postcodes follow alphabetical order of districts. For the UK I would struggle to come up with a logical order and it would just look a lot more messy overall. But if you can point me to a good source for the UK telephone numbering plan, I could try that instead.