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A Wendover Productions video on how dollar store chains expanded across America and why they displace grocery stores in small towns. It covers their business model and supplier leverage.

3Blue1Brown explains why plotting primes in polar coordinates produces spiral patterns, using modular arithmetic, Dirichlet's theorem and rational approximations of pi.

aGameScout explains rolling, the third major NES Tetris playstyle, in which players tap the back of the controller to move pieces faster than hypertapping. It covers how the technique works and where it comes from.

Marques Brownlee explains why iMessage's blue and green bubbles matter, covering the technical, commercial and social side of Apple's messaging lock-in. It also discusses RCS and what could be done about it.

Applied Science explains how retail anti-theft tags work. A tiny magnetostrictive strip acts as a mechanical oscillator excited by a magnetic field, and magnetizing or demagnetizing it arms or disarms the tag.

CGP Grey's video "Humans Need Not Apply" argues that automation will make a large part of the workforce economically obsolete, much as engines did for horses. It surveys robots and software replacing both physical and mental labor.

Technology Connections takes apart a 1940s Sunbeam Radiant Control toaster. It senses the toast's own browning and lowers and raises it automatically using purely mechanical parts and no electronics.

Technology Connections explains how old-fashioned non-electronic rice cookers work, using a magnet and spring switch tripped by the Curie point. It shows the thermodynamics and magnetism behind a simple appliance.

Adam Savage and engineer Zach Radding examine Lumafield CT scans of Apple's $130 Thunderbolt 4 cable alongside cheaper USB-C cables. They explain the internal components that distinguish Thunderbolt from ordinary USB-C.

Vox breaks down how great rappers build rhymes, from Kurtis Blow's simple bars to Biggie's smooth flow and Kendrick Lamar's dense, fast delivery. It uses on-screen visualizations of rhyme structure.

PBS Space Time explains what happens as you approach and cross a black hole's event horizon, using Penrose diagrams and light cones as the tool for understanding spacetime there.

A PBS Space Time episode asking what black holes really are and whether events can happen inside them. It covers event horizons, time dilation and common misconceptions about black holes.

Technology Connections looks at why awnings disappeared from houses and how effective they are at cutting solar heat gain and cooling costs. It argues they are a simple, forgotten cooling technology.

A Business Insider World Wide Waste episode on H&M's garment recycling machines, which turn used clothing into new apparel. It asks whether a fast fashion company can solve the waste problem it helped create.

A SAAMI-produced training video for firefighters explaining what happens when sporting ammunition burns, including that unchambered cartridges lack the energy to penetrate much. It includes test footage of ammunition in fires.

Hugh Jeffreys tears down the iPhone 12 and assesses its repairability, focusing on how parts are serialized and tied to the device so swapping components between phones does not work.

A short video telling how Xerox PARC invented the graphical user interface and how Steve Jobs's 1979 visit influenced Apple's Lisa.

Wendover Productions explains how UK rail privatization worked and why it failed. It covers the fragmented operator and infrastructure structure and why market forces apply poorly to rail.

Tom Scott's video whose title shows its own live view count, and the story of how he made that work. It explains why open APIs were once common and why they largely disappeared.

A two-minute animation of an Alan Watts talk arguing that life is like music: it is meant to be danced to in the moment, not rushed toward a final goal. It is a short, accessible take on living in the present.

Practical Engineering's explanation of the February 2021 Texas winter storm and the resulting power grid outage. It lays out the facts about ERCOT, the grid's isolation, and how generation across fuel types failed in the cold.

PBS Space Time explains the proposal to use the Sun's gravity as a giant lens, sending a train of small light-sail spacecraft to the focal point roughly 550 AU out. It covers how such a telescope could image exoplanets in surprising detail and the engineering challenges involved.

An animated 11-minute tour of the whole field of mathematics as a single map, showing how pure and applied math and their sub-fields relate to each other.

An animated simulation comparing single-winner voting methods such as plurality, instant runoff and STAR. Colored regions show which candidate wins as a randomized electorate shifts across a two-dimensional political space, building on Ka-Ping Yee's earlier diagrams.

Technology Connections explains that US household power is split-phase, with two 120V legs that combine to 240V for large appliances. It covers the breaker panel and how the system works.

A short animated TED-Ed lesson in which two competing ice cream vendors on a beach illustrate why rival shops cluster together. It introduces game theory and the Nash equilibrium through the Hotelling model.

A Technology Connections video essay on how analog and digital clocks shape different mental models of time, with the minute hand acting as a progress indicator.

Technology Connections examines an old feature-rich microwave and shows how it uses a humidity or steam sensor and lookup data to cook food well, arguing it beats many modern ones.

Part 3 of Kirby Ferguson's Everything is a Remix series, using Apple and the iPhone to show how invention builds on copying and combining prior ideas. It argues that creativity and innovation are inseparable from copying.

PBS Space Time explains Roger Penrose's conformal cyclic cosmology, in which the far future of our universe becomes the big bang of the next. It explores what could come after the universe ends.

Technology Connections praises a 1940s-50s Sunbeam toaster and explains what makes a toaster well designed, drawing on a vintage Sunbeam video.

Kurzgesagt's animated overview of human origins and the vast prehistory before recorded history. It covers how modern humans emerged and spread.

Technology Connections explains what forced-air furnaces are, how they work and why they need electricity. He covers combustion, airflow and the parts of a modern furnace.

Practical Engineering explains why San Francisco's Millennium Tower is sinking and tilting, covering how geology and foundation design (friction piles in the Colma Formation) affect skyscrapers. It also covers the fix being attempted.

JerryRigEverything tours Li-Cycle to show how lithium-ion batteries from EVs, phones and tools are recycled. It walks through the process of shredding batteries and extracting materials.

Tom Scott tours Ocado's automated grocery warehouse, where thousands of robots move boxes on a grid called the Hive, and asks whether they are individual robots or a hive mind.

Chubbyemu narrates the true case of a professor who spilled two drops of dimethylmercury on her hand and suffered fatal neurological damage.

Technology Connections explains how a home can act as a thermal battery by pre-cooling or pre-heating when electricity is cheap or abundant. He shows how this shifts load off-peak and eases strain on the grid.

Stand-up Maths explains why the perimeter of an ellipse has no simple closed-form equation, showing the infinite series and presenting approximation formulas.

Practical Engineering summarizes the 2017 Oroville Dam spillway failure, explaining the engineering details behind the incident. It also discusses how operators and regulators failed to keep downstream residents safe.