Referring to the diagram[3] on Wikipedia, a concave hole is first cut into the stone. Parts 1 and 2 of the lewis are inserted, one at a time. Inserting part 3 between 1 and 2 results in all three locking into place. A pin and ring at the top keeps the 3 parts from separating.
[1] https://www.romanbaths.co.uk
[2] https://bathgeolsoc.org.uk/journal/articles/2021/2021_Moving...
[3] https://en.wikipedia.org/wiki/Lewis_(lifting_appliance)#/med...
And another on building a working reproduction: https://www.youtube.com/watch?v=BGHq4O-ib2U&list=PLZioPDnFPN...
https://www.google.com/maps/place/Spiral+Bridge/@53.2849203,...
https://www.google.com/maps/place/Spiral+Bridge/@53.2850202,...
For a slightly more modern example, take European Gothic Cathedrals. People weren't guessing, they weren't improvising, and they weren't relying on intuition - if they did most of them would have collapsed long ago.
These structures were made without blueprints, and often many of the head masons may have been illiterate, but a knowledge of forms and rules such as "the thickness of the wall of an arch should be a bit more than a fifth the span of the arch" allowed for reliably producing stable structures.
These rules were less precise than modern engineering math and mean that many of the structures are overengineered / have higher margins of error than are considered necessary in modern construction, but they are not based on intuition or guessing.
BTW, Hammurabi was particularly dastardly in his building code specifications. You could, of course, be put to death if a building or wall collapsed and killed someone. But that was just table stakes. Even Ur-Nammu had that much figured out.
Hammurabi added on to the punishment by forcing you to rebuild the wall..
to the specifications of reputable builders..
at your own expense..
and then be put to death.
Don't even get me started on Asian "building codes" back in the day.
HN user Arainach is right, no one was guessing, or intuiting, while building in a lot of these empires. It was wayyy too risky. Pretty much everyone was following rules passed down by the builders for centuries. In some cases, millennia. Only an actual ruler would dare even consider deviating from the known good building forms.
So, you don't believe roofs were invented until very recent times? The only building I've ever been in where roof collapse couldn't be fatal is my neighbor's chicken coop.
> Castles and cathedrals and city walls and the like don't fall down unless you intentionally ignore or obfuscate a ton of cracking a slumping and things moving, etc, etc.
Easily disproven. Here's one refutation:
https://en.wikipedia.org/wiki/Erfurt_latrine_disaster
Seriously: your lack of knowledge about historical architecture is impressive.
There are many failure modes other than gradually cracking and eventually failing. Even in that case, by the time you notice such cracking, the cost of repair - if it can be repaired - is dramatically higher, and has tons of effects.
Photos cannot be rare. Physical copies of a photograph might be. Photos are by their nature singular instances of artistic or technical action, so all of them are equally rare.
"Photo" means both the image itself and a physical copy of said image. So if you agree that physical copies can be rare, then either you agree that photos can be rare or you are idiosyncratically using a different definition of "photo" than everyone else.
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