Looking At How Pyramids Were Built Using Their Casing Stones

November 4, 2023 by Maya Posch 23 Comments

As one of the most famous Ancient Egyptian pyramids, the Pyramid of Khafre on the plateau of Giza has been a true wonder of the Ancient World ever since its construction around 2570 BCE. Today, well over 4,500 years later, we are still as puzzled as our ancestors over the past hundreds of years how exactly this and other pyramids were constructed. Although many theories exist, including ramps that envelop the entire pyramid, to intricate construction methods from the inside out, the only evidence we have left are these pyramids themselves.

This is where the jokingly called [History for Granite] channel on YouTube has now pitched some new ideas, involving the casing stones that used to fully cover the Pyramid of Khafre, prior to widespread theft and vandalism.

Bonding stones within the casing stones on the Pyramid of Khafre. (Credit: History for Granite, YouTube)

Despite the pyramids of Giza in particular being a veritable tourist trap, said tourists are heavily discouraged from climbing onto the pyramids, or even set up high-powered camera gear on tripods near them. Even with drone footage available, it was necessary to get a zoomed-in look on the casing stones that remain on the pyramid of Khafre near its top at well over 100 meters. Working within these limitations, it was possible to take detailed photos of three sides of the pyramid, which revealed interesting details.

In the top screenshot from the video the top of the pyramid is visible, which gives some indication of just how much the pyramid may have shifted out of alignment due to earthquakes over the millennia. This turned out to be not significant enough to account for some purported ‘gaps’ between the casing stones, with supposed ‘filler material’ from scaffolding holes explainable as just broken off sections of these casing stones. What was more interesting was that a pattern could be found in so-called bonding stones.

Pattern of bonding stones on the north face of the pyramid of Khafre. (Credit: History for Granite, YouTube)

These bonding stones have a slanted end, so that they can be lifted slightly above a matching slanted stone, before being lowered to complete a row of bricks or stonework. After analyzing the three faces of the still mostly intact casing stones, a clear pattern emerged, such as that on the north face, pictured here.

What this suggests is that each row of casing stones were laid down by multiple groups of workers, each starting at a specific point before coming together where those sections would be joined with a bonding stone. This lends credence to the theory that the pyramid was constructed layer by layer, including the outer covering. To further examine these clues, the even older Bent Pyramid at the royal necropolis of Dahshur with mostly intact casing stones will be examined in more detail next.

If anything this series shows just how much there still is that we don’t know about these massive construction projects that are really only preceded by the works of the Sumerian and Akkadian people.

Continue reading “Looking At How Pyramids Were Built Using Their Casing Stones” →

Saving Apollo By Decoding Core Rope

November 4, 2023 by Jonathan Bennett 7 Comments

One of our favorite retro hardware enthusiasts, [CuriousMarc], is back with the outstanding tale of preserving Apollo Program software, and building a core rope reader from scratch to do it. We’ve talked about [Marc]’s previous efforts to get real Apollo hardware working again, and one of the by-products of this effort was recovering the contents of the read-only core rope memory modules that were part of that hardware.

The time finally came to hand the now-working Apollo guidance computer back to its owner, which left the team without any hardware to read core rope modules. But the archive of software from the program was still incomplete, and there were more modules to try to recover. So, the wizardly [Mike Stewart] just decided to roll up his sleeves and build his own reader. Which didn’t actually work as expected the first time.

And this leads us into one of [Marc]’s elevator music explainers, where he gives a beautiful rundown on how core rope works. And if you are thinking of core memory based on ferrite cores, get ready for a brain stretch, as core rope is quite a bit different, and is even more complicated to read. Which brings us to the bug in [Mike]’s reader, which is actually a bug in the block II design of the core rope modules.

Reading a byte off the module requires setting multiple inhibit wires to select an individual core. An innovation in block II allowed those inhibit wires to run at half current, but it turns out that didn’t actually work as intended, and partially selected multiple cores on the other half of the module. And [Mike] forget to re-implement that bug — the reader needs to literally be bug-for-bug compatible. A quick recompile of the FPGA code makes everything work again. And the conservation effort can continue. Stay tuned for more in the Apollo story!

Continue reading “Saving Apollo By Decoding Core Rope” →

NFTs And Tulipmania: A Little Bit Of History Repeating

October 20, 2023 by Al Williams 123 Comments

We were not surprised to read that a company that tracks NFTs declared that most NFTs are now worthless. But the NFT — non-fungible token — market was huge, so around 23 million people invested in NFTs that are now worth nothing. Worse still, the company notes that because of oddities in how NFTs are priced, the real number of worthless assets is probably even greater than they think.

It is easy to look back and think that it was obvious. After all, an NFT of the Mona Lisa isn’t really the Mona Lisa. Nor does owning it confer any real benefit other than “bragging rights” of owning an NFT of the Mona Lisa. But that’s like saying Luke should have known Darth Vader was his father — it’s only evident after the fact. History is replete with bad ideas at the time that paid out down the road. Of course, history is also full of bad ideas that were simply bad ideas. For every Apple or Google stock you didn’t buy at $4 a share, there are a hundred $4 stocks that you shouldn’t have bought.

The Virus

The NFT craze was sort of a viral event. We usually think of these as part of the Internet culture, but that’s not really true. There is actually very little new on the Internet. The Internet just lets things reach further and faster than before.

Don’t believe me? Kilroy was a viral meme in the 1940s. Fads such as hula hoops, phone booth stuffing, and flagpole sitting were the ice bucket challenges of their day. But, of course, these things weren’t economic. Just fun fads. But economic fads that turn out to be a bad idea are nothing new, either.

Continue reading “NFTs And Tulipmania: A Little Bit Of History Repeating” →

You’ve Got Mail: Grilled, Scrambled, And Other Delicious Stamps

October 19, 2023 by Kristina Panos 8 Comments

Well, we’re just zipping right through this series, no? So far we’ve looked at various postal machines and how they work to flip mail around, cancel the postage, and sort it, all in a matter of seconds. We explored the first automated post office and found out why it was a failure, and we learned why it all depends on ZIP code. Now, it’s finally time for some really fun stuff: the stamp trivia.

Now I’m no philatelist by any standard, though I do have a few hundred stamps strewn about the house. The danger in philately is that you learn all sorts of cool things about stamps and their history, and you just want to buy more and more of them. So let’s go!

Continue reading “You’ve Got Mail: Grilled, Scrambled, And Other Delicious Stamps” →

You’ve Got Mail: It All Depends On ZIP Code

October 12, 2023 by Kristina Panos 26 Comments

Previously on You’ve Got Mail, we looked at a few services that were designed to speed up the mail at various points along the way. But these improvements were all taking place on the USPS’ side of the the fence. Was there anything the customer could be doing to help out?

As it turns out, yes. And it was almost too late. Whereas you could once address a letter or postcard simply to “Fred Minke, Somerset, Wis.” and it would reach him, the volume of mail was getting completely out of hand with the rise of computers, automated billing, and advertising. Something was needed to improve routing and speed up delivery.

We all know enough about ZIP codes to use them, but where did they come from? How many types are out there? What do they even mean? Let’s find out.

Continue reading “You’ve Got Mail: It All Depends On ZIP Code” →

Tech In Plain Sight: Skyscrapers

October 11, 2023 by Al Williams 3 Comments

It is hard to imagine that for thousands of years, the Great Pyramid of Giza was the tallest manmade structure in the world. However, like the Lincoln Cathedral and the Washington Monument, which also held that title, these don’t count as skyscrapers because they didn’t provide living or working space to people. But aside from providing living, retail, or office space, skyscrapers also share a common feature that explains why they are even possible: steel frame construction.

Have you ever wondered why pyramids appear in so many ancient civilizations? The answer is engineering. You build something. Then, you build something on top of it. Then you repeat. It just makes sense. But each upper layer adds weight to all the lower layers, so you must keep getting smaller. Building a 381-meter skyscraper like the Empire State Building using self-supporting walls would mean the ground floor walls would be massive. Steel lets you get around this.

In Antiquity

You might think of high-rise buildings as a modern thing, but that’s actually not true. People seem to have built up to the best of their abilities for a very long time. Some Roman structures were as high as ten stories. Romans built so high that Augustus even tried to limit building height to 25 meters — probably after some accidents. In the 12th century, Bologna had as many as 100 towers, one nearly 100 meters tall.

There are many other examples, including mudbrick structures rising 30 meters in Yemen and 11th-century Egyptian structures rising 14 stories. In some cases, building up was due to the cost or availability of property. In others, it was to stay inside a defensive wall. But whatever the reason, self-supporting walls can only go so high before they are impractical.

So steel and iron frames grabbed the public’s attention with things like Joseph Paxton’s Crystal Palace in 1851, and Gustav Eiffel’s Tower in 1887.

Continue reading “Tech In Plain Sight: Skyscrapers” →

Why Walking Tanks Never Became A Thing

October 2, 2023 by Lewin Day 67 Comments

The walking tank concept has always captured imaginations. Whether you’re talking about the AT-AT walkers of Star Wars, or the Dreadnoughts from Warhammer 40,000, they are often portrayed in fiction as mighty and capable foes on the battlefield. These legged behemoths ideally combine the firepower and defense of traditional tanks with the versatility of a legged walking frame.

Despite their futuristic allure, walking tanks never found a practical military application. Let’s take a look at why tracks still rule, and why walking combat machines are going to remain firmly in the realm of fiction for the foreseeable future.

Continue reading “Why Walking Tanks Never Became A Thing” →