Right, lets bounce a few more of these wild stabs in the dark away.

First, the myth that for short pieces of glass it won't make any difference. (By the way it would be nice if you guys would present some maths to the contrary, instead of me proving me right. Why don't you prove me wrong?)

So as posted above they make glass up to 3m wide. Someone else spotted they cut 6000mm x 3200mm panels from another source. So lets say the glass is only 6m long. Not a huge stretch of the imagination for a glass industry with a half kilometre bit of kit. We also know from the British Glass .pdf that they can make panels as thin as 0.4mm. This time I will do all the maths in metric so there is no imperial voodoo getting in the way.

The radius of earth (according to RE laws) is 6371km. If I move across the surface tangentially 1 kilometre I form a triangle. The hypotenuse is going to be the radius of the earth + my distance above it. I.E the error given by following the earth's curve. Or how much you guys would have them shave away.

So with Pythagoras

(6371 * 6371) + (1 * 1) = 40589642 km^2

Square rooting this will give my hypotenuse

=6371.00007848061480 km

So my error over a kilometre piece of glass is 6371.00007848061480 km - 6371 = 0.00007848061480 km

That is 0.07848061 metres

That is 7.848061 centimetres for every kilometre of glass.

That is 78.48061 mm for every kilometre of glass.

Now hopefully you agreed that a 6m piece, wasn't out of the question?

1000/6 = 166.666666

So I will divide my 1km error by 166.66666 recurring to give me 6m of glass.

so 78.48061 mm of glass divided by 166.66666666 = 0.4708836888 mm

We already know they make glass only 0.4mm thick so how can they shave 0.47mm out of it? They would have no glass left in a 6m panel. And as for tolerances? If something bends by 117.5% of its entire thickness over just 6m does that suggest 'Perfectly flat, flaw-free glass?".

The maths is all there. Please before screaming foul-play, check it for yourself. There is no trickery in it. Pick up a calculator.

Now for any flat fluid related posts. Pick up a physics book. For a round earth FLUIDS FOLLOW THE CURVATURE OF THE EARTH no matter what you put them on. You dump them on a platform and they will bend in the shape of the earth on that flat platform. They will form a bulge perfectly matching the earth's circumference. Gravity will act on them and pull them towards the centre of the earth. Not straight down below it.

Thank you for the kind words above about this being a clever post. It is a damn sight harder to prove something no one believes, than it is to just regurgitate stuff you learnt from school (albeit poorly in some of the cases above).

As for consistency, if the glass bends 3 inches over half a kilometre, that will produce a bulge of 1 and a half inches. 1 and a half inches up the parabola. One and a half down it again.