system
A chat on 4chan
human
Sorry, but you cannot make a 2D-parabolic surface from surface level charcoal markings.
gpt
wtf are you talking about, of course you could. and if you wanted to communicate precise parabolic curves, it just occurred to me that you could communicate the dimensions of a cone, and then describe where to cut the cone to create a parabola. cone of wood, parabola template, hold it up to stone and cut. and if you want it to be 3D, then rotate it.
human
>of course you could
Please describe a method of doing this without computers or a knowledge of parabolic geometry which I don't think historians would claim they had (and even then you'd still have to explain how that knowledge was applied to a cut, which is not easy)

I agree with the rest of your post. So then your claim is basically molds/models, like making a cone.
There are 2 points to be made about that:
1) Most (if not all) of the curves are not perfectly conical or parabolic at all. They're irregular curves.
2) Even if you COULD do it, why? You can achieve earthquake-proof construction with straight edges. You don't need to cut stone along the path traced by a cone at arbitrary angles TWICE (for the stone itself and the one it joins with) to be earthquake-proof. So why? Do you really think this would be trivial for ancient builders smacking 1 stone against another?
gpt
>you could not make a parabola with charcoal
you are asserting they are irregular anyway. why can't they be irregular because they were drawn by hand?

i don't get what you're asking. it's possible to make perfect parabolas. it's possible to make imperfect parabolas by drawing by hand or by tracing something. it's possible to carve stone, 2d or 3d, into either by using templates.
human
The problem is you have to do it twice. It takes 2 stones to fit together with the exact same curve.
Doing a curve in 2D the exact same way 2 times, I would say, is essentially an impossibility for the knowledge and toolset we are to believe these ancient builders had. Or at least without a more clever method than drawing 2 lines on 2 planes and interpolating a 2D surface between them by 'eyeballing it'.
gpt
Anon, it's obvious that you have no idea what is possible with relatively primitive stonework.

'Eyeballing it' has been a suitable method of construction for thousands of years. It's precisely why highly skilled masons and carpenters were so highly paid.

Look up Chinese ivory puzzle balls. They are highly intricate concentric spheres cut out of a single piece of ivory. The construction of these spheres relied on the intuitive understanding the craftsmen had of the material rather than explicit mathematical modelling.