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In September 2024, Hurricane
Helene struck the southeastern US,
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causing widespread damage to lots of regions
that rarely see storms as severe as this one.
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The mountains in western North
Carolina were hit particularly hard,
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with entire towns washed away by the flooding.
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It will probably be months, or even
years before the region fully recovers.
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But the disaster could have an unexpected impact
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on the rest of the world, too.
Specifically, on our technology.
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Because pretty much every silicon
computer chip in the world exists
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thanks to one mineral deposit in a tiny
town in the North Carolina mountains.
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[intro music]
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This story begins about 450 million years ago,
with something called the Taconic Orogeny,
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one of the many phases of tectonic activity
that formed the Appalachian Mountains.
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As two tectonic plates converged,
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dense oceanic crust was pushed under
the roots of the continental plate,
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forming sheets of rock that were thrust over
existing layers, fittingly called thrust sheets.
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The friction between these two plates raised the
temperature enough to melt the solid rock below.
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That molten magma then forced its
way up through the surrounding rocks,
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creating huge blobs of granite called plutons,
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and big cracks filled with
volcanic fluid called pegmatites.
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When this happens, that volcanic fluid cools
down and the minerals in it form crystals.
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The longer this cooling process
takes, the bigger the crystals.
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And because all this was
happening so deep in the crust,
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the fluid in the cracks
solidified /extremely/ slowly,
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allowing it to separate out
into big, pure mineral crystals.
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Fast forward a few hundred million years,
and the movement of the tectonic plates
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eventually brings the plutons and the
pegmatites closer to the Earth’s surface,
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in the Blue Ridge Mountains in North
Carolina, near the small town of Spruce Pine.
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The pegmatites in Spruce Pine are made
up of about 65% feldspar, 25% quartz,
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and 8% mica. As a bonus, there are some gemstones
like aquamarine and emerald mixed in, too.
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And because of all these great crystals, people
have mined the area for thousands of years.
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Historically, Native Americans living
in the region would extract mica and
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carve it into figurines or use it as currency.
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Then, during the late 1800s, Spruce
Pine became a full-on mining town.
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But the funny thing is, even though nowadays
the region is most famous for its quartz,
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they were mining out pretty
much everything except quartz.
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The big flat sheets of mica made great
stove windows and electrical insulators,
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and the feldspars were used
in ceramics and glassmaking.
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Extracting the feldspar involved crushing
up the rock, submerging it in water,
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and using air to skim off what you want.
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Everything else, including the quartz,
was considered waste and thrown away.
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It took a while for anyone to realize
just how special that quartz really was.
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See, even though it’s the second-most
common mineral in our Earth’s crust,
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not all quartz is created equal.
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When the crystals grow, sometimes little
impurities get stuck in there, too.
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And sometimes that’s considered a good thing,
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since that’s how we get the fancy
varieties of quartz like amethyst or agate.
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But the impurities change more
than just the color of the crystal:
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they can also change its physical and
chemical properties, which can make it weaker.
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So while amethyst looks great on your bookshelf,
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it’s less great in the kinds of
industrial applications where
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you really need consistency and predictability.
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For these applications, high purity
quartz becomes the special sauce.
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This purity is measured in percentages
of inclusions, or in parts per million.
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A medium level of purity is considered to
be quartz with 0.1% other elements mixed in,
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or 100 parts per million of impurities.
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While the highest purity quartz has no more than
0.003%, or 30 parts per million of other stuff.
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And that quartz at Spruce Pine that
people used to think was waste?
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Well, it turned out that it had fewer impurities
than any other natural quartz we’ve found,
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at just between 25.9 and 13.4 parts per million.
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When the mining companies in Spruce Pine noticed
the purity of their so-called waste quartz,
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they started selling it,
too. And in the beginning,
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it was used to make everyday glass
products, like bottles and windows.
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It was even used to make a 5 meter wide,
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20 ton mirror for a telescope that was built
in the 1940s, and is still in use today.
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But Spruce Pine’s quartz really got its
big break with the dawn of the digital age,
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when the world began to run on
silicon-based computer chips.
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Today, silicon chips run pretty
much all of our modern technology.
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They’re in our computers, phones and tablets,
and pretty much anything else that goes beep,
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from barcode scanners to wind turbines.
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And even in your pets, if they’ve got microchips!
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To make these fancy chips, the ideal mineral to
use is silicon, because it’s a semiconductor.
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A semiconductor is just a thing that can either
conduct electricity or insulate against it,
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depending on the other chemical
elements that are added to it.
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So because the exact chemical makeup of
your semiconductor changes its properties,
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for a consistent microchip product,
you need super-pure silicon.
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All chips start out as a slice of
a single, perfect, silicon crystal,
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which is manufactured using something
called the Czochralaski process.
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It starts with pure quartz sand, which gets
heated up with carbon to remove the oxygen,
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leaving behind 98% pure silicon.
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Then you do a few other chemical
processes to increase the purity
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to somewhere around 0.01 parts per billion.
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That means that for every hundred billion atoms
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of silicon you’ll only have a
single atom of something else.
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This ultrapure silicon is then
put into a crucible and heated
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to precisely 1,413 degrees Celsius
to melt it down into silicon soup.
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You then dip a seed crystal of silicon into
the top surface of the molten silicon pool and
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drag it upwards, veeery slowly, so it grows
into a crystal of exactly the right shape.
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The result is a perfect cylindrical
crystal of silicon, called a boule,
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with no irregularities and nothing else mixed in.
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Finally, the boule is cut into circular
wafers roughly half a millimeter thick,
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which are polished and made
into countless computer chips.
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So this whole thing starts with quartz
and we’ve been obsessed with purity,
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so you’d think that the Spruce Pine
quartz is what makes those chips, right?
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Wrong!
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See, even though the Czochralski process starts
with quartz, that quartz gets purified a ton
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anyway, so you can take any old junky
quartz and turn it into silicon chips.
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So you don’t need Spruce Pine quartz to make
the chips. You need it to make the crucible.
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For those of us who skipped blacksmithing lessons,
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a crucible is just a container
that you melt stuff in.
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It needs to be heat-resistant enough to
hold your melted stuff, and it also needs
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to be made of something that isn’t reactive
and won’t taint that melted stuff, either.
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They’re usually made of metal, or clay, or
porcelain. Or in this case, extremely pure quartz.
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Crucibles for the Czrochralski process are made
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by taking ultrapure quartz sand and
heating it up to fuse it into shape.
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The final product has a melting
temperature of around 1700 degrees celsius.
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And these crucibles don’t last forever.
Over time, the molten silicon starts to
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eat away at the crucible, which is
exactly why it needs to be so pure.
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Any impurities in the crucible have a
chance of getting into your liquid silicon,
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which could affect how the crystal grows.
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The purer your crucible, the
less chance of that happening.
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So it seems like a simple thing,
but the silicon semiconductor
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industry really hinges on the supply
of these ultrapure quartz crucibles.
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Bad crucibles means bad crystals, no
usable silicon wafers and no… well
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anything technological, really.
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In 2015, it was estimated that we used around
30,000 tons of ultrapure quartz per year,
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and up to 90% of that comes from Spruce Pine.
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Plus in the nearly ten years
since that figure came out,
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it’s almost guaranteed that that number’s gone up.
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Not bad for a town with just 2500 people!
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But that’s ultimately what makes
the situation so precarious. It’s
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a single point of failure for a
multi-billion dollar industry.
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Which brings us back to the storm that got
so many people talking about this place.
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Hurricane Helene struck Spruce Pine in
the early hours of September 27th 2024.
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It had been downgraded to a tropical
storm by the time it got there,
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but the storm still did a
surprising amount of damage.
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Roads and buildings were destroyed or washed away,
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and thousands of people lost
power or water to their homes.
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As of this recording , there are
at least 96 confirmed deaths,
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and dozens more who are still missing.
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And because of all this devastation,
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the quartz mines have shut down,
and only one is back up and running.
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Meaning that the world’s supply of ultrapure
quartz will be impacted for as long as the
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other mine is down, and possibly for longer
as they both try to make up for lost time.
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Now, there are some other deposits of
ultrapure quartz in places like Russia,
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China and Brazil, but none are quite as pure
or as plentiful as the quartz from Spruce Pine.
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And while it’s technically possible to
purify lower-quality quartz or to make
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synthetic ultrapure quartz, nobody’s really doing
either of those things at an industrial scale.
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They’ve never had to, because Spruce
Pine quartz has always been there.
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Until now.
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To be clear, there isn’t any reason to panic and
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start hoarding silicon chips
like toilet paper in 2020.
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Plenty of companies have stockpiles of
silicon wafers for situations just like this,
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so the mine being closed isn’t an immediate
problem for computer chip production.
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But if mining is down for more than a few
months, and that stockpile becomes depleted,
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then we could be looking at a major supply
chain issue for basically the whole tech world.
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The last time something like this
happened was during the pandemic,
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when everyone realized they didn’t want
to be stuck inside without a screen,
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and demand for tablets, computers and consoles
temporarily but expensively outstripped supply.
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But this time it would be the other way round.
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The world would still have its everyday demand for
computer chips, but the supply would be the issue.
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As availability of the remaining
wafers diminished, prices for
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all tech could skyrocket, not just the
stuff you can watch YouTube videos on.
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And we don’t know how bad the problem really is.
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Ultrapure quartz mining is a secretive business,
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so the mining companies have thus far been
pretty cagey about just how bad the damage was.
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For now, we’ll just have to
sit tight, and wait and see.
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It’s kind of crazy to think about how every
piece of technology we use, from microwaves
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to TVs and cell phones to singing greeting
cards, could only exist because of one place.
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One weird quirk of geology when
two plates collided gave us the
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exact ingredient we needed to be
able to make any of this possible.
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So thanks Spruce Pine, for being
the unofficial partner and sponsor
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of basically everything we’ve ever
looked at on a screen. We owe you one.
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[Outro music]
