two-factor authentication

Two Minute Papers covers a paper on speeding up fluid and smoke simulation with convolutional networks. It contrasts the approach with earlier regression forest methods.

An 8-minute explainer on the Lightning Network and how it relates to Segwit, Bitcoin and Litecoin. It covers how off-chain payment channels route payments to scale blockchain transactions.

3Blue1Brown's first chapter on deep learning explains what neurons and layers are and the math underlying a basic neural network, using handwritten digit recognition with visual animations.

A Two Minute Papers episode on NVIDIA's recurrent denoising autoencoder, which cleans up noisy Monte Carlo path-traced image sequences. It shows how a neural network can produce usable renders from very few samples.

Two Minute Papers covers OpenAI's multi-agent hide-and-seek experiment, in which agents learned emergent tool use and found ways to break the game's rules. It summarizes the 'Emergent Tool Use from Multi-Agent Interaction' paper.

CGP Grey explains first-past-the-post voting and why it pushes elections toward two dominant parties. It is the first in his series on electoral systems.

CGP Grey explains Mixed-Member Proportional representation, the system used in New Zealand where voters get two votes. It covers how it differs from first-past-the-post.

Mark Handley of UCL explains, with simulation visualizations, how early Starlink satellites without inter-satellite links could still give low-latency wide-area communication by hopping via ground relays. He shows it can beat fibre on many long paths.

Vsauce explores math through card tricks and big numbers, including an animation of how enormous 52 factorial, the number of deck orderings, really is.

Sabine Hossenfelder explains how close nuclear fusion really is to break-even, and why headlines about ITER and lab milestones are misleading. She distinguishes plasma gain (Q plasma) from whole-system gain (Q total) and shows the latter is still far below one.

Ward Cunningham explains the history and intent of the debt metaphor, which he coined while refactoring the WyCash product. He says debt means code reflecting an incomplete understanding of the problem, not sloppy programming.

3Blue1Brown's third deep learning chapter gives a visual, intuitive account of backpropagation and what happens to a neural network as it learns. A follow-up video covers the underlying calculus.

A Vox Borders episode with Johnny Harris explaining how China is gradually erasing the line between mainland China and Hong Kong since the 1997 handover. It describes the one country, two systems arrangement and its expiration date.

Mark Handley of UCL looks at how SpaceX's November 2018 revisions to the Starlink constellation affect network behavior. The video visualizes the orbits and routing and estimates latencies, building on his earlier video and research paper.

MinutePhysics explains Shor's algorithm, showing how a quantum computer factors large integers by finding the period of a number modulo N. It walks through the modular arithmetic and number theory that give the exponential speedup over classical factoring, and why this threatens encryption.

A short cartoon explaining how language models like ChatGPT work, from autocomplete and conditional probabilities to neural networks, gradient descent and backpropagation. It shows how networks act as universal function approximators.

An episode of Journey to the Microcosmos, hosted by Hank Green, about diatoms, single-celled algae with glass shells. It covers their role in producing a large share of Earth's oxygen and their uses in beer filtering, paint and kitty litter.

3Blue1Brown's chapter 4 on deep learning gives a more formal, symbol-based account of backpropagation calculus, connecting the intuition from the previous chapter to the math found in textbooks and code.

Harvard professor Arthur Brooks explains why boredom is useful rather than something to avoid. He describes how a wandering mind engages the brain's default mode network, which supports creativity and curiosity, and suggests it may protect against depression.

CGP Grey explains the history and legal status of territorial claims on Antarctica. It covers the overlapping national claims and the Antarctic Treaty that freezes them.

A Kurzgesagt video on the conditions in which most farm animals are raised. It argues that cruelty is for cheaper rather than better meat, and that a small price increase per meal could avoid most of the suffering.

A Kurzgesagt animated explainer on meat: why people love it and what it costs animals, the environment and health. It lays out the complicated trade-offs of meat production and consumption.

About Here explains how North American building codes requiring two staircases make small multi-story apartment buildings hard to build, and contrasts this with places that allow single-stair designs.

Autoline's John McElroy and Caresoft president Terry Woychowski look at the BYD Seagull, an electric hatchback that sells in China for about $11,500. Woychowski points out the cost-saving design and manufacturing choices, and McElroy takes it for a short test drive.

A rap battle in which John Maynard Keynes and F. A. Hayek debate the causes of boom and bust, stimulus, and bailouts. It was produced by Econstories to teach the two schools of thought.

A short explainer on the history and mechanics of public key cryptography and the Diffie-Hellman key exchange. It uses a mixing-paint-colors analogy to show how two parties can agree on a shared secret in public.

A 10-minute 3Blue1Brown chapter explaining the determinant as the factor by which a linear transformation scales area or volume. It builds the idea geometrically with animations before any formulas.

CGP Grey explains split-brain patients, where severing the corpus callosum lets the two hemispheres act independently. He uses this to explore the idea of two minds in one head.

Mike Pound explains the discrete cosine transform and how it underpins JPEG compression. It is part two of Computerphile's JPEG series.

Real Engineering explains how Zipline built a drone delivery network for medical supplies in Rwanda. It covers the fixed-wing drones, catapult launch, parachute drop and the logistics behind the service.

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.

A short clip from Carl Sagan's Cosmos in which he explains how Eratosthenes measured the circumference of the Earth using shadows in two Egyptian cities. It is a clear, visual account of an ancient scientific feat.

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 Wendover Productions explainer on how China built the world's largest high-speed rail network so quickly and why its rail strategy differs from America's. It covers politics, social benefits and the economics of unprofitable lines.

PBS Space Time explains the Hubble constant tension, in which two precise, independent methods of measuring the universe's expansion rate disagree. It covers why this calls some standard cosmology into question.

A Blender-animated explanation of the Toyota Hybrid Synergy Drive, showing how the engine, two motor-generators, planetary gearset and battery work together as an eCVT.

The Thought Emporium's update on the home-brewed gene therapy he took to cure his lactose intolerance. It reports how the effect held up over two years and what future versions might look like.

An RSA Animate summary of Iain McGilchrist's lecture on the divided brain, arguing the brain's two hemispheres attend to the world differently and that this has shaped culture and society.

Jen Simmons explains the difference between CSS Flexbox and CSS Grid, and when to use each. She makes the case that Grid does not replace Flexbox and most sites use both.

AVweb's Paul Bertorelli explains why general aviation has failed to replace leaded avgas, blaming industry inertia, bureaucratic delay and an exemption that removes the incentive. This is part one of two.