These past few months, I’ve found myself pondering the value of a good puzzle. Are they really just for clever people to show off? Is there any practical value to be derived from them? We know from archaeologists that in ancient times, prosperous times were marked by a proliferation of the arts, but during hard times, artisans were forced to make their crafts more practical. As the process repeated, generations of artisans would proliferate during times of plenty, to be winnowed into a smaller pool of inventors, who found themselves at the cutting edge of new industries. Lather, rinse, repeat: the cycle of innovation.
One area where we see this interplay between the practical and the artistic crafts is in the relationship between locks and mechanical puzzles. Many locksmiths made puzzles as side products, and by turns, a clever mechanical puzzle might inspire an innovative lock. One could imagine an amusing puzzle like Locked Sticks might have contributed to--or been derived from--the invention of tumblers for door locks, and any of our Puzzle Locks could actually function as a padlock, despite being made of wood. Same like Puzzle Boxes that today are sold for their entertainment value, they are as good or better at securing valuables than more ordinary jewelry boxes, were originally used by samurai and warlords to pass messages securely. Travelers also used them, to keep their valuables safe while on the road and craftsmen to keep there tools.
In the search for practical puzzles, we must avoid the bias to see practicality where it doesn’t exist. For example, it’s often said puzzle rings ensured fidelity because they can’t be removed without falling apart, but it’s actually quite easy. The myth that they served a practical purpose is is from modern salespeople embroidering their products as “Turkish wedding rings” or “Harem rings,” and ascribing any sexism or impracticality to some strange and exotic place.
Meanwhile, locks are clearly practical assets, and the provenance for their relationship with puzzles goes all the way back to barred doors in Mesopotamia and Egypt (around 2000 BCE). The obvious disadvantage to barred doors was that the bar could only be removed from inside, so this led to the first keys: angled pieces of wood with metal studs (usually bronze) that could be inserted into a slot in an exterior bar. These studs were of the precise spacing and length to push three dangling tumblers up to be flush with the bar and allow the door to open. The Romans took the same model and made it out of metal rather than wood, using very precise design to allow them to be smaller and therefore harder to pick.
While wooden locks like those used by the Egyptians were found as far away as Sweden and Cyprus, they didn’t always lead to the same innovations. The Celts developed a different design for a door lock using a bar on the inside, with a long metal key with two hooks on the end that was inserted into a hole in the door to lift wooden tumblers on either side of the hole. This sounds more like our modern keys and keyholes, especially in how the key had to be inserted vertically and then turned horizontal in order to lift the tumblers with the hooks. One can only imagine what the Romans thought when they encountered this innovation. It made for a much more secure door, but it limited the amount of variety in the designs so that many doors were accessible to many keys. Combining the best of each design with parallel innovations from Greece, sliding bolt locks soon appeared all over.
As metallurgy became more specialized, in allowed for increasingly precise casting and shaping of locks, which eventually led to them being so small they were portable: the first padlocks. At this point, the relationship between puzzles and locks becomes so intertwined that they were almost interchangeable. The puzzle padlocks used by the ancient Romans and Celts were also known as “mask locks” because they were usually fashioned with the face of a person or a deity, with a ring that was fastened around a leather money bag to prevent tampering. Each of these required a key to open them--usually fashioned so that it could be worn as a ring--but they also had secret switches that had to be pressed in order for the key to work, making them much more like puzzle boxes than modern padlocks.
Of all the faces carved on these locks, the two-faced god Janus was among the most popular, and it makes sense why. Not only was he the god of the transitions and passageways these bags would go through, but he granted sentries, guards and bodyguards the ability to remain watchful, and if I were a courier carrying one of these bags, I would want eyes in the back of my head! After all, the purpose of the lock was less to ensure the safety of the contents as it was meant to ensure the loyalty of the courier: if the bag and lock didn’t arrive intact, the contents were assumed to have been tampered with, and everyone knew who to blame.
The practice of using padlocks to ensure a courier’s loyalty remains to this day, a testament to the fact that locks and security are mostly about reducing the amount of trust needed in a relationship. What does this mean for the future, especially in light on the claims of cryptocurrency to allow for “trust-less” exchanges of value? A previous entry about the P vs. NP problem noted that if that problem was ever answered with P = NP, it could spell the end of the modern data encryption that makes cryptocurrency work. It seems unlikely, but stranger things have happened in the world of mathematics. If that’s the world we wind up in, it will be a financial mess, and we’ll all have to go back to the drawing board and build a better lock. Again.
Thanks for puzzling with me.