Freezing Fog

It's not a cosy day outside - it's probably not got above freezing all day.  And the fog means you can't see more than a 100 meters.

At the top of this you can the word DIN followed  by some numbers - DIN is the Deutsches Institut für Normung (German institute for standardisation).  You see this mark everywhere.

You even get it on packs of paper - DIN 476 is the standard that states the correct sizes for A-series paper (A1, A2, A3 and the ubiquitous A4).  What was a surprise to learn is there are B-series & C-series sizes. B4 is bigger than A4 and C4 is somewhere in the middle.

You never stop learning.