Day 149/19. Her Majesty and her Toroids

This is the Queens head on a standard £1.00 coin. Nothing special there...but look closer.
In a previous life I worked with Core Memory. Many decades ago this was leading edge technology. I did keep some demonstration samples from that time and found them today in a drawer while looking for something else. Each of these were used in computer memory components and could store 1 bit of data each.
These are 13 Mil Cores, thats 13/1000 of an inch in diameter or around 0.3 mm. You do need to be careful handling them as ingesting these into your body is really not a good idea.