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441 Curated Videos · Brain-Score 75+/100

Books & Mental Models / Bücher & Denkmodelle

Curated mental models from non-fiction books, biographies of scientists and inventors, systems thinking, and decision-theory videos with 3-point Blueprints.

Brain-Score 95/100 Ergodicity TV · 19:12

Random multiplicative dynamics -- Ole Peters

  1. A random process breaks ergodicity when its ensemble expectation value across parallel systems diverges from its long-time trajectory rate.
  2. In a fair coin toss gaining 50% on heads and losing 40% on tails, the ensemble average grows 5% per round while single trajectories decay.
  3. Because individuals cannot average across parallel clones, long-run wealth follows the time average, converging continuously to GBM.
Ergodicity BreakingEnsemble vs Time AverageMultiplicative Coin-Toss GameGeometric Brownian Motion (GBM)Stochastic Differential Equations
Brain-Score 95/100 Primer · 13:17

Simulating the Evolution of Aggression

  1. Foraging simulations pit peaceful Doves that share contested food against aggressive Hawks that fight at a survival cost.
  2. Neither pure strategy is stable alone: Hawks invade peaceful Dove groups, but Hawk-on-Hawk fights ruin an all-Hawk population.
  3. Equating expected payoffs yields an evolutionarily stable mixed Nash equilibrium confirmed by multi-generation simulations.
Hawk-Dove GameNash EquilibriumEvolutionary Game TheoryPayoff MatrixAgent-Based Simulation
Brain-Score 95/100 engineerguy · 11:45

Building a Cathedral without Science or Mathematics: The Engineering Method Explained

  1. Medieval masons built tall stone cathedrals without formal math by favoring pointed arches over semicircular Roman ones.
  2. Draping a rope along an arch template and folding it into thirds gave a geometric rule of thumb for safe wall thickness.
  3. The engineering method uses empirical rules of thumb to solve practical problems long before complete scientific theory.
The engineering methodPointed Gothic archRope-thirds geometry ruleEmpirical rules of thumb
Brain-Score 95/100 The Synthetic Mind · 2:58

Why Bayes' Theorem Is So Powerful

  1. For a 1% rare disease, a 90%-sensitive test with 9% false alarms flags 9 sick and 89 healthy per 1,000, giving only ~9% true risk.
  2. Bayes' theorem multiplies the prior by the likelihood and divides by total positives so large healthy base rates are not ignored.
  3. Follow-up positives raise probability from 9% to ~50% and ~91% only if tests fail independently and the prior fits your symptoms.
Bayes' TheoremPrior, Likelihood & PosteriorNatural FrequenciesBase-Rate NeglectSequential Independent Updating
Brain-Score 95/100 Scott Manley · 13:54

What Does "Set SCE To AUX" Mean Anyway - Apollo 12's Lightning Strike Explained

  1. Lightning strikes at 36s and 52s tripped dV/dt overload sensors, disconnecting all three fuel cells from Apollo 12's main bus.
  2. Signal Conditioning Equipment (SCE) scales diverse spacecraft sensor readings into 0–5V signals for ground telemetry.
  3. Switching SCE to its AUX power supply tolerated low bus voltage, restoring telemetry so crews could reconnect the fuel cells.
SCE-to-AUXSignal Conditioning28V DC Power BusFuel CellsSpacecraft Telemetry
Brain-Score 95/100 3Blue1Brown · 21:14

The medical test paradox, and redesigning Bayes' rule

  1. Even a highly accurate test can have low predictive value when a condition's prior prevalence in the population is very rare.
  2. Tests do not state your probability of disease directly; instead, new evidence updates your prior chances upward or downward.
  3. Expressing Bayes' rule as prior odds multiplied by the Bayes factor enables fast mental estimates and prevents base-rate neglect.
Bayes' Rule (Odds Form)Bayes FactorLikelihood RatioPrior OddsBase-Rate Neglect
Brain-Score 95/100 Visual Electric · 41:05

The Story of Information Theory: from Morse to Shannon to ENTROPY

  1. Building on Morse, Baudot, Nyquist, and Hartley, Claude Shannon formalized information entropy as average symbol surprise.
  2. Assigning shorter variable-length codewords to more probable symbols compresses messages toward the entropy limit.
  3. Long block codes and the Shannon-Hartley theorem define the maximum rate for virtually error-free noisy communication.
Shannon entropyVariable-length prefix codingHartley information measureNoisy-channel block codingShannon-Hartley theorem
Brain-Score 94/100 Historian`s Front · 1:55

The Spitfire’s Wing Was Hard to Build, and Worth It

  1. The Spitfire's elliptical wing housed 8 guns and gear while staying 13% thick at the root and 9% at the tip for speed.
  2. Elliptical lift minimized tip-vortex drag, and a 2.5-degree twist made the root stall first to keep ailerons working.
  3. Five nested square spar tubes and 20% lower wing loading than the Bf 109 enabled tighter turns despite hard tooling.
Elliptical wing planformAerodynamic washout (2.5°)Nested square-tube sparLeading-edge torsion boxWing loading physics
Brain-Score 94/100 Vsauce · 20:20

The Zipf Mystery

  1. Zipf's Law shows that word frequency across languages scales as 1 over rank, plotting as a straight power-law line on log-log axes.
  2. Zipf's Principle of Least Effort models language as a balance between speakers minimizing words and listeners needing precision.
  3. Preferential attachment—demonstrated by randomly linking paperclips—naturally produces skewed Zipfian and Pareto distributions.
Zipf's LawPower-Law DistributionPareto Principle (80/20)Principle of Least EffortPreferential Attachment
Brain-Score 94/100 The Film Gate · 8:36

Kelly Johnson talks about his greatest creation the SR-71, Uncut interview. | Stock Footage

  1. Pratt & Whitney J58 engines operate as turbojets up to 1,600 mph before shifting cycle to ramjet-like thrust with 35% from ejectors.
  2. Boundary air mixed around the 3,500 °F exhaust prevents melting, while a 30,000-lb moving titanium-tip spike positions shockwaves.
  3. Engineered in 1958 with slide rules, conical wing camber and fuselage chines cut supersonic drag and radar cross-section.
Pratt & Whitney J58 engineTranslating inlet spikeTail air ejectorConical wing camberFuselage chines
Brain-Score 94/100 Jason Collins · 8:05

Anomalies in expected utility theory: The Allais paradox

  1. In Kahneman and Tversky's Allais experiment, over 80% pick a sure $2,400 first yet switch to a 33% $2,500 gamble in the second pair.
  2. Simplifying both preferences produces opposite expected-utility inequalities, proving no consistent utility function fits both choices.
  3. The reversal breaches the Independence of Irrelevant Alternatives axiom when a shared 66% outcome shifts from $2,400 to $0.
Allais ParadoxExpected Utility TheoryIndependence AxiomCertainty EffectPayoff-Chance Lotteries
Brain-Score 94/100 Mustard · 10:50

The Jet Train Should've Changed the World

  1. Jean Bertin's 80-seat French Aérotrain i80HV topped 250 mph using a 400 hp lift turbine and a 12,000+ lbf turbofan.
  2. Air-cushion pads hovered 0.25 inches off guideways, while British RTV-31 and US UTACV designs tested linear induction motors.
  3. Hovertrains lost to incremental wheelset, track, and signaling upgrades across nearly a million miles of existing rail.
Aérotrain i80HVAir-cushion lift padsTurbofan propulsionLinear induction motorRail network economics
Brain-Score 94/100 Visual Electric · 14:59

The Story of the Telegrapher's Equations - from nowhere an unknown genius solves transmission lines

  1. William Thomson modeled submarine telegraph cables as distributed resistance and capacitance governed by Fourier's heat diffusion law.
  2. At age 26, self-taught physicist Oliver Heaviside incorporated Maxwellian inductance—voltage drop opposing current acceleration.
  3. Uniting diffusion with inductance yielded the Telegrapher's Equations, revealing wave propagation and reflections on transmission lines.
Telegrapher's EquationsDistributed RC Line ModelHeat Diffusion AnalogyInductance (dI/dt)Transient Wave Propagation
Brain-Score 93/100 Real Engineering · 16:30

What Actually Happened to the Concorde

  1. Investigators traced Air France 4590's runway debris to a 42 cm wear strip shed by a DC-10 just five minutes before takeoff.
  2. Fracture analysis of the Hiduminium AU2GN aluminum fuel tank revealed matte 45-degree rupture faces from tensile necking.
  3. Those 45-degree shear surfaces proved the wing tank failed via static overload rupture rather than gradual fatigue cracking.
Fracture MechanicsHiduminium AU2GN45-Degree Static RuptureDuctile NeckingForensic Maintenance Audit
Brain-Score 93/100 Cengiz Turkoglu · 4:10

Reason explains Swiss Cheese Model

  1. Serious accidents combine an initiating error, failed detection, and missing recovery controls, making human error a system failure.
  2. Every safeguard—training, procedures, supervision, and inspection—has shifting holes, so zero past accidents never proves safety.
  3. Disasters strike when flaws align across all defensive slices at once, as shown by repeated airline engine-pin failures worldwide.
Swiss Cheese ModelLatent System FlawsDefense in DepthError Detection & RecoverySafety Complacency Trap
Brain-Score 93/100 Primer · 18:22

Simulating the Evolution of Teamwork

  1. Simulates evolving agent populations across game-theory payoff matrices to test when teamwork survives selfish defectors.
  2. In one-shot Prisoner's Dilemma payoffs, defection dominates because exploiting cooperators yields higher immediate fitness.
  3. Derives Evolutionarily Stable Strategy conditions showing how Stag Hunt payoffs or partner assortment sustain cooperation.
Evolutionary game theoryPayoff matrixPrisoner's DilemmaEvolutionarily stable strategyAgent-based simulation
Brain-Score 93/100 Asianometry · 34:50

TSMC's First Breakthrough: The Copper/Low-K Interconnect Transition

  1. Explains IC metallization and why aluminum interconnects hit severe RC delay limits at shrinking process nodes.
  2. Traces IBM's copper interconnect breakthrough and the engineering hurdles of low-k dielectric integration.
  3. Analyzes how TSMC outcompeted UMC across the 180nm and 130nm transitions by mastering copper/low-k fabrication.
Copper interconnectsLow-k dielectricsRC delay optimizationIC metallization180nm & 130nm process nodes
Brain-Score 93/100 Mustard · 14:48

This Jet Changed Everything

  1. After midair breakups doomed Britain's Comet jetliner, Boeing shifted from preventing failure to designing planes to survive it.
  2. Engineers hung engines on underwing pylons with shear fuse pins so a failing engine breaks free without tearing off the wing.
  3. Even after an inverted roll proved jet safety, Douglas's 6-abreast DC-8 showed cabin economics mattered as much as prototypes.
Fail-Safe Design ThinkingUnderwing Engine PylonsShear Fuse PinsPressurization FatiguePrototype vs Cabin Economics
Brain-Score 93/100 Real Engineering · 26:57

The Insane Engineering of the Concorde

  1. Olympus 593 square inlets used variable ramps and spill doors to slow supersonic air to subsonic flow for the compressors.
  2. Supersonic airframe heating expanded the Concorde by 20 cm on every flight, creating severe thermal fatigue cycles.
  3. Engineers selected WWII-era Hiduminium RR58 aluminum alloy over costly titanium to handle heat at viable structural weight.
Olympus 593 TurbojetVariable Intake RampsHiduminium RR58 AlloyDelta Wing AerodynamicsThermal Fatigue Design
Brain-Score 93/100 Veritasium · 27:18

Once you understand game theory, you understand the world.

  1. One-shot Prisoner's Dilemma traps rational players in mutual defection, while repeated rounds unlock long-term cooperation.
  2. In Axelrod's tournaments, Tit for Tat beat deceptive strategies by being nice, retaliatory, immediately forgiving, and clear.
  3. When signal noise turns mistakes into apparent betrayals, Generous Tit for Tat (~10% forgiveness) stops retaliation spirals.
Iterated Prisoner's DilemmaTit for TatGenerous Tit for TatNon-Zero-Sum GamesAxelrod's Tournament
Brain-Score 92/100 Mutual Information · 9:01

The Kelly Criterion

  1. In repeated positive-expectation bets, wagering an optimal fixed fraction of wealth outperforms constant-dollar bet sizing.
  2. The Kelly Criterion selects the exact wealth percentage that maximizes the expected logarithmic growth rate across trials.
  3. When true probabilities are merely estimated, full Kelly bets suffer sharp growth drops, demanding smaller risk-adjusted wagers.
Kelly CriterionLogarithmic wealth growthProportional bet sizingParameter estimation risk
Brain-Score 92/100 Rational Animations · 19:08

How to systematically approach truth - Bayes' rule

  1. Models beliefs as probabilities and updates hypotheses systematically when new evidence arrives via Bayes' rule.
  2. Derives conditional probability, P(H|e) posterior updating, and the practical odds form of Bayes' theorem.
  3. Applies Cromwell's rule to show why empirical beliefs should never be dogmatic and must stay open to evidence.
Bayes' rule P(H|e)Conditional probabilityOdds form of Bayes' ruleCromwell's ruleBayesian epistemology
Brain-Score 92/100 Curious Droid · 16:33

How did NASA get those great film shots of Apollo and the Shuttle?

  1. NASA used explosion-proof 400 fps film cameras and quartz pad mirrors because film offered wider dynamic range than early video.
  2. Optical trackers like the 24-inch, 12,700 mm ROTI telescope used radar and sensitive joysticks to film staging 65 km high.
  3. Over 130 pad cameras and WB-57 aircraft at 60,000 ft captured engineering data crucial for analyzing launch anomalies.
High-Speed Film (400 fps)Quartz Pad MirrorsROTI Tracking TelescopeCine-Sextant MountWB-57 Chase Aircraft
Brain-Score 92/100 Scott Manley · 13:36

The Most Launched Rocket - A History Of The R-7

  1. Sergei Korolev's 280-ton R-7 lit four LOX/kerosene strap-on boosters and a core stage together to launch Sputnik 1.
  2. Continuous engineering iterations adapted the R-7 into Luna, Vostok, Voskhod, Molniya, and Soyuz over 1,000+ launches.
  3. Modern variants added Fregat upper stages, while Soyuz-2.1v paired an NK-33 engine with four RD-0110R steering nozzles.
R-7 SemyorkaLOX/kerosene boostersKorolev crossSoyuz launch vehicleNK-33 engine
Brain-Score 92/100 Clever at War · 1:42

Why the First Jet Airliner Was Sunk in a Giant Water Tank #shorts

  1. Cruising near 35,000 ft subjected the de Havilland Comet's pressurized cabin to cyclic swelling and shrinking on every flight.
  2. To test cyclic fatigue safely, engineers submerged a Comet fuselage in water and pumped pressure cycles until it burst at ~3,000 flights.
  3. Recovered wreckage traced the fatal crack to a rivet hole at a square roof radio-antenna window, reshaping airliner testing.
Cyclic Metal FatigueFull-Scale Water Tank TestCabin Pressurization CyclesRivet-Hole Stress Concentration
Brain-Score 92/100 Khan Academy · 9:20

Prisoners' dilemma and Nash equilibrium | Microeconomics | Khan Academy

  1. In a 2x2 payoff matrix, two suspects face 2 years if both deny, 3 years if both confess, or 1 vs 10 years if one defects.
  2. Confessing is the strictly dominant strategy for each suspect regardless of whether the other confesses or denies.
  3. Mutual confession forms a stable 3-year Nash equilibrium, showing rational choices can miss the 2-year global optimum.
Prisoner's DilemmaNash Equilibrium2x2 Payoff MatrixDominant StrategyGame Theory
Brain-Score 92/100 Ergodicity TV · 15:18

What is ergodicity? - Alex Adamou

  1. A stochastic process is ergodic only when one system's long-term time average equals the ensemble average across many systems.
  2. Independent coin tosses and stationary mean-reverting processes are ergodic because single trajectories match ensemble expectations.
  3. In multiplicative non-ergodic processes, the ensemble average can grow exponentially while nearly every individual trajectory decays.
ErgodicityTime vs Ensemble AverageStochastic ProcessesExpectation ValueMultiplicative Dynamics
Brain-Score 92/100 securitylectures · 44:01

Hamming, "You and Your Research" (June 6, 1995)

  1. Richard Hamming argues doing significant engineering or science requires tackling important problems rather than routine tasks.
  2. Avoid chasing only grand Nobel-scale leaps; instead plant tractable 'acorn' problems that can grow into major breakthroughs.
  3. Reserve 10% of your week—such as uninterrupted Friday afternoons—to examine field fundamentals and steer long-term direction.
Hamming Questions10% Friday Great-Thoughts TimeAcorn-to-Oak Problem SelectionFirst-Principles FundamentalsDirected Effort vs. Random Walk
Brain-Score 92/100 Marginal Revolution University · 4:47

A Price Is a Signal Wrapped Up in an Incentive

  1. A price acts as a signal wrapped in an incentive, communicating resource scarcity while rewarding substitutes and conservation.
  2. Rising 1970s oil prices made heating U.S. greenhouses costly, shifting rose cultivation to sunny climates in Kenya and Ecuador.
  3. Without central planning, price signals coordinate dispersed local knowledge so scarce oil flows to high-value uses like jet fuel.
Price as Signal & IncentiveDispersed KnowledgeSubstitution EffectEmergent Market CoordinationOpportunity Cost Reallocation
Brain-Score 92/100 TED-Ed · 5:44

How to outsmart the Prisoner’s Dilemma - Lucas Husted

  1. In a one-shot Prisoner's Dilemma, mutual betrayal forms a Nash Equilibrium because neither player gains by cooperating alone.
  2. In infinitely repeated games, a grim-trigger strategy cooperates daily but punishes any single betrayal forever.
  3. Solving the infinite payoff series shows cooperation is optimal whenever future payoffs carry a discount factor of at least 1/3.
Prisoner's DilemmaPayoff matrixNash EquilibriumDiscount factor (delta)Infinite geometric series
Brain-Score 92/100 Physics Explained Simply · 21:07

Feynman's FIRST PRINCIPLES: The Truth About How Genius Works

  1. First principles thinking involves breaking down complex ideas to their fundamental truths, rather than memorizing facts or jargon.
  2. The Feynman technique encourages explaining concepts simply to an imaginary newcomer to identify gaps in one's own understanding.
  3. True expertise comes from rebuilding knowledge from scratch, questioning assumptions, and understanding the underlying mechanisms, not just surface-level information.
First principlesFeynman techniqueMental modelsCritical thinkingDeep understanding
Brain-Score 92/100 Asianometry · 18:31

A Brief History of Semiconductor Packaging

  1. Level-1 IC packaging mounts sliced silicon dies onto metal lead frames with fine bond wires to shield chips from damage.
  2. Early aerospace hermetic TO-5 metal and ceramic cans were heavy, costly, and capped I/O at roughly 8 to 10 pins.
  3. Fairchild pioneered plastic encapsulation and Rex Rice's 0.1-inch inline through-hole leads for wave soldering.
Lead frameWire bondingTO-5 packagePlastic encapsulationThrough-hole wave soldering
Brain-Score 92/100 Historian`s Front · 2:05

Why the Corsair’s Wings Are Bent

  1. The F4U Corsair's 2,000 hp Pratt & Whitney R-2800 engine required a 3-blade propeller over 4 meters wide to generate thrust.
  2. An inverted gull wing dropped the lowest bend near the deck, giving propeller clearance with short, sturdy carrier landing gear.
  3. Gear legs rotated 90° to retract flat into the wing, while outer wing panels folded upward at the bend to save carrier space.
Inverted gull wingPratt & Whitney R-28004m three-blade propeller90-degree retracting gearFolding carrier wings
Brain-Score 92/100 Real Engineering · 24:41

The Floating Harbors of D-Day

  1. Mulberry harbors enabled landing 675,000 troops, 150,000 vehicles, and 690,000 tons of supplies within two months of D-Day.
  2. Layered breakwaters paired scuttled blockships, deep-water Bombardon floats, and sunken concrete Phoenix caissons to calm seas.
  3. Concrete Beetle pontoons, steel tidal pontoons, and spud piers supported flexible floating bridges across full tidal swings.
Mulberry HarboursPhoenix Concrete CaissonsBombardon BreakwatersBeetle PontoonsSpud-Leg Pier Bridges
Brain-Score 91/100 Marginal Revolution University · 8:15

The Coase Theorem

  1. The Coase Theorem shows externalities persist when property rights are vague and transaction costs block private bargaining.
  2. Steven Cheung proved beekeepers and farmers price pollination directly because short bee flight keeps bilateral bargaining cheap.
  3. Where millions face high bargaining costs, defining property rights enables market solutions such as tradable permits.
Coase TheoremTransaction CostsProperty Rights AllocationInternalizing ExternalitiesTradable Permits Market Design
Brain-Score 91/100 Art of the Problem · 10:01

The Enigma Machine (how it worked & why it was cracked)

  1. Three 26-position Enigma rotors stepped through 17,576 letter shifts, inside a total keyspace over 150 quintillion.
  2. Fatigued operators reused predictable starting rotor positions instead of random ones, exposing the rotor wirings.
  3. Because Enigma never mapped a letter to itself, the Allied Bombe used plaintext cribs to find daily keys in minutes.
Enigma rotor machinePolyalphabetic substitutionKeyspace analysisKnown-plaintext cribsAllied Bombe machine
Brain-Score 91/100 Mustard · 14:08

Could This Change Air Travel Forever?

  1. NASA engineer Robert T. Jones proved an asymmetrical oblique wing cuts high-speed drag while pivoting straight for slow flight.
  2. Unlike dual-hinge swing wings, a single central pivot is lighter and keeps the center of lift nearly stationary across angles.
  3. NASA flew subsonic oblique testbeds and designed a $36M supersonic F-8 Crusader demonstrator before 1986 Navy budget cuts.
Oblique wing aerodynamicsSingle-pivot wing structureCenter-of-lift stabilityTransonic drag reductionFly-by-wire F-8 testbed
Brain-Score 91/100 Clever at War · 1:38

Why the F-117 Has No Curves #shorts

  1. Applying Pyotr Ufimtsev's radar diffraction math on 1970s computers forced Lockheed's Echo code to model flat panels.
  2. Angled flat facets deflected radar waves away, shrinking the F-117's radar cross-section to about 0.001 square meters.
  3. Because the faceted airframe was unstable in pitch, roll, and yaw, an F-16 fly-by-wire computer stabilized it continuously.
Ufimtsev diffraction mathLockheed Echo RCS solverFaceted stealth geometryFly-by-wire stabilizationRadar cross-section
Brain-Score 91/100 Real Engineering · 18:02

The Insane Engineering of the P-47 Thunderbolt

  1. Water injection cooled cylinder hotspots to stop pre-ignition on compression strokes, unlocking emergency horsepower.
  2. Its Double Wasp radial engine, supercharger ducting, self-sealing tanks, and armor survived heavy combat damage.
  3. Despite high fuselage weight and parasitic drag in turns, pilots exploited superior high-altitude speed and dive energy.
Double Wasp Radial EngineWater InjectionSupercharger DuctingSelf-Sealing Fuel TanksParasitic Drag
Brain-Score 91/100 iluli by Mike Lamb · 5:39

The Myth of Experience: Kind and Wicked Learning Environments

  1. Kind learning environments like cycling give immediate, accurate feedback, whereas wicked environments give delayed, noisy signals.
  2. Mistaking complex domains like business for kind environments causes us to draw false causal lessons from personal experience.
  3. Asking "what is missing?" and "what is irrelevant?" uncovers hidden confounders such as supply shocks and seasonal cycles.
Kind Learning EnvironmentsWicked Learning EnvironmentsFeedback Loop DelayMissing-Information AuditConfounding Variables
Brain-Score 91/100 Then & Now · 14:30

Thomas Kuhn: The Structure of Scientific Revolutions

  1. Kuhn argues science alternates between normal puzzle-solving under shared rules and revolutionary paradigm shifts.
  2. Persistent anomalies strain reigning paradigms, as oxidized metals gaining weight undermined phlogiston theory.
  3. Air pumps and precision scales enabled Priestley and Lavoisier to overthrow phlogiston and establish a new paradigm.
Normal ScienceParadigm ShiftScientific AnomaliesPhlogiston CrisisPuzzle-Solving Model
Brain-Score 91/100 Clinical Leadership Solutions Ltd · 3:14

Reasons Swiss Cheese Model

  1. Complex systems prevent harm through layered barriers whose shifting holes cause accidents only when every layer aligns.
  2. Defense holes stem from front-line active failures—slips, lapses, mistakes, and violations—plus dormant latent flaws.
  3. Because human fallibility is inevitable, safety countermeasures must redesign work conditions, equipment, and staffing.
Reason's Swiss Cheese ModelActive vs Latent FailuresSlips, Lapses & MistakesLayered System DefensesSystems Safety Design
Brain-Score 91/100 Primer · 12:22

Simulating Supply and Demand

  1. Agent-based simulations model sellers with minimum acceptable prices and buyers with maximum willingness-to-pay limits.
  2. Agents adjust price expectations after each trade or miss until competing buyers and sellers reach equilibrium.
  3. Markets self-organize to generate economic surplus, acting as neutral allocation tools with real-world trade-offs.
Agent-Based SimulationSupply & Demand CurvesEquilibrium PriceEconomic SurplusPython & Blender
Brain-Score 91/100 Undefined Behavior · 10:14

Is Democracy Impossible? (Arrow's Theorem)

  1. Arrow's Impossibility Theorem proves no ranked voting system with three or more options satisfies fairness without a dictator.
  2. Flipping voters' top rankings one by one isolates a single pivotal voter whose pairwise preference dictates the group outcome.
  3. Ranked systems incentivize strategic ballot lying and two-option equilibria unless ballots capture richer voter information.
Arrow's Impossibility TheoremSocial choice theoryUnanimity conditionPivotal voter proofStrategic voting
Brain-Score 91/100 O'Reilly · 5:10

Algorithms to Live By - Brian Christian

  1. Frames everyday choices between proven favorites and new options through computer science's explore-exploit trade-off.
  2. Uses the multi-armed bandit problem to show why uncertain options with high upside merit testing beyond raw expected value.
  3. Links logarithmic-regret algorithms and developmental psychology to explain why young children explore and elders exploit.
Explore-Exploit Trade-OffMulti-Armed Bandit ProblemExpected ValueLogarithmic Regret
Brain-Score 91/100 Asianometry · 23:38

National Semiconductor: "Animals of Silicon Valley"

  1. Charlie Sporck revived National Semiconductor via ruthless cost cuts, independent sales reps, and early offshore fabs in Singapore.
  2. Steady linear analog chip profits contrasted with failed downstream bets on consumer calculators, NS16000 CPUs, and Itel mainframes.
  3. After divesting VIA x86 and AMD Geode lines, National sold its 12,000-product analog portfolio to Texas Instruments for $6.5B.
Operational cost disciplineOffshore chip assemblyLinear & analog IC moatDownstream diversification trapSemiconductor industry history
Brain-Score 91/100 Curious Droid · 9:51

X-15 The Ultimate Flying Machine

  1. Air-launched from a B-52 at 45,000 ft, the rocket-powered X-15 set a manned aircraft record of Mach 6.72 (7,273 km/h).
  2. Its XLR99 rocket engine burned its fuel in two minutes, carrying test pilots above 100 km to a peak of 107.8 km.
  3. The extended X-15A-2 tested hypersonic aerodynamics, dummy ramjets, and spray-on ablative heat shields for spacecraft.
North American X-15XLR99 rocket engineB-52 air launchAblative heat shieldHypersonic flight
Brain-Score 91/100 Mustard · 10:10

The Air Force’s Crazy 747 Aircraft Carrier Concept

  1. Boeing's 1973 USAF study proposed a 747 internal hangar carrying 10 micro-fighters launched and rearmed at Mach 0.85.
  2. Traces airborne carrier precursors from USS Akron and Macon trapeze airships to Cold War B-36 parasite-fighter tests.
  3. Mid-air docking turbulence, micro-fighter capability limits, and practical aerial refueling led USAF to shelve the plan.
Boeing 747 AACParasite micro-fighterTrapeze docking bayIn-flight refueling
Brain-Score 91/100 selcuk ozyurt · 14:20

(AGT11E12) [Game Theory] Vickrey–Clarke–Groves (VCG) Mechanism (a.k.a Pivotal Mechanism)

  1. Built on Groves schemes, the VCG mechanism chooses an efficient social decision maximizing the sum of reported utilities.
  2. Each agent's transfer subtracts the maximum total utility all other agents could achieve if that player were absent.
  3. Transfers are always non-positive—needing no external funds—and align incentives by charging pivotal agents their externality.
VCG (Pivotal) MechanismGroves SchemeDominant-Strategy IncentiveSocial Utility MaximizationMarginal Social Externality
Brain-Score 91/100 Primer · 20:49

Simulating the Evolution of Sacrificing for Family

  1. Hamilton's rule (rB > C) predicts altruism evolves when recipient benefit times genetic relatedness exceeds personal cost.
  2. Agent-based blob simulations show self-sacrifice dies out among strangers but thrives when directed toward close kin.
  3. Measuring relatedness relative to baseline population gene frequency explains cooperative trade-offs under competition.
Hamilton's rule (rB > C)Kin selectionExpected value mathAgent-based simulationUnity & Manim
Brain-Score 91/100 Asianometry · 22:18

What Happened to the Capacitors in 2002?

  1. Aluminum electrolytic capacitors roll etched anode and cathode foils with electrolyte-soaked paper and an oxide dielectric.
  2. Motherboards use dozens of E-caps to smooth rectified AC ripple into steady DC and decouple CPUs from voltage spikes.
  3. Heat and flawed electrolyte chemistry raise Equivalent Series Resistance (ESR), generating gas until cans bulge or burst.
Electrolytic CapacitorAluminum Oxide DielectricEquivalent Series ResistanceDecoupling CapacitorBridge Rectifier
Brain-Score 91/100 CLExchange · 3:48

Introduction to Causal Loops

  1. Causal loop diagrams replace linear cause-and-effect thinking with circular feedback showing how actions alter system states.
  2. Reinforcing loops compound change in one direction, whereas balancing loops oppose change to seek a goal or oscillate.
  3. Plus (+) and minus (-) link polarities track directional coupling, while boxed stocks highlight key accumulations in a loop.
Causal Loop DiagramsReinforcing Feedback LoopsBalancing Feedback LoopsLink Polarity (+ / -)Stock & Flow Mapping
Brain-Score 90/100 Historian`s Front · 1:46

How a Bomber Engine Made the Fw-190

  1. Replacing the Fw 190's high-altitude-limited radial with a 35 L inverted V-12 Jumo 213 required a 50 cm rear plug.
  2. An annular radiator ring behind the propeller cooled engine liquid while preserving a streamlined radial-like nose.
  3. MW 50 water-methanol injection cooled supercharged air to stop knock, boosting power past 2,000 hp at 6,600 m.
Jumo 213 inverted V-12Annular nose radiatorMW 50 water-methanol boostFuselage CG balancing
Brain-Score 90/100 Clever at War · 1:39

This Plane Was Dropped From a Bomber to Fly #shorts

  1. In 1947, the Bell X-1 used an alcohol-LOX rocket to target 800 mph at 35,000 ft, where cold air lowers the speed of sound.
  2. Propellant made up nearly half its 12,250 lb launch mass and burned out in 5 minutes, so a B-29 dropped it at 23,000 ft.
  3. Its sole 1949 runway takeoff burned 90 seconds of fuel reaching 23,000 ft, proving why air-launch and dry-lake gliding were vital.
Bell X-1 rocket planeAlcohol-LOX rocket engineB-29 air-launch mothershipDead-stick glide landing
Brain-Score 90/100 William Spaniel · 17:04

Game Theory 101 (#72): The Winner's Curse, Part 1

  1. Unlike private-value second-price auctions where bidding true value is dominant, common-value auctions rely on noisy signals.
  2. Applying Bayes' rule updates posterior probabilities of an oil field's true worth ($0, $25M, or $50M) given a high signal.
  3. Bidding naive signal-based expected value causes the Winner's Curse and negative payoffs; bidders must condition on winning.
Winner's CurseCommon-Value AuctionsSecond-Price AuctionsBayes' Rule UpdatingConditional Expected Value
Brain-Score 90/100 Bloomberg Originals · 4:31

How Toyota Changed The Way We Make Things

  1. Faced with post-WWII scarcity, Taiichi Ohno modeled Just-In-Time production on US supermarkets, making parts only to replace used stock.
  2. Kanban cards tracked parts across production stages, while overhead cords let any worker stop the entire assembly line to fix defects.
  3. Paired with Kaizen continuous improvement, Toyota cut assembly to 1.6 man-hours per car by 1972 and inspired Lean across global industries.
Toyota Production System (TPS)Just-In-Time (JIT) Pull FlowKanban Visual SchedulingOverhead Line-Stop CordKaizen Continuous Improvement
Brain-Score 90/100 Principles by Ray Dalio · 30:46

How The Economic Machine Works by Ray Dalio

  1. Economies run on repeated money-and-credit transactions shaped by productivity growth plus short-term and long-term debt cycles.
  2. Credit boosts spending and incomes faster than productivity short term, but causes deflationary deleveraging when debts outgrow income.
  3. Three rules govern stability: keep debt growth below income, keep income growth aligned with productivity, and raise productivity.
Short-Term Debt CycleLong-Term Debt CycleCredit vs. MoneyEconomic DeleveragingProductivity Growth
Brain-Score 90/100 Thomas Nechyba · 6:28

27.2.The Hotelling Model

  1. Under Bertrand competition with identical goods, price competition drives equilibrium price down to marginal cost.
  2. In Hotelling's fixed-price model on a uniform interval, two firms converge to the midpoint Nash equilibrium with zero differentiation.
  3. In a two-stage game where product location precedes pricing, firms maximally differentiate in stage one to soften price competition.
Hotelling Spatial ModelBertrand Price CompetitionNash EquilibriumMinimum vs Maximum DifferentiationTwo-Stage Sequential Game
Brain-Score 90/100 Maxwell Debun · 1:44

The World War II Engine Every Mechanic Hated #radialengine #engineering #ww2 #engine

  1. Inline engines grow too heavy and high-drag at high cylinder counts, while aligned radials starve rear rows of air.
  2. The Pratt & Whitney R-4360 offset 28 cylinders into four helical seven-cylinder rows so air hit every cooling fin.
  3. Supercharged across 71 liters with 56 spark plugs and dual magnetos, it kept balanced cooling for heavy WWII bombers.
Pratt & Whitney R-4360Helical cylinder offsetAir-cooling finsDual magneto ignitionSupercharger
Brain-Score 90/100 William Spaniel · 11:01

Game Theory 101 (#40): Hotelling's Game and the Median Voter Theorem

  1. In Hotelling's spatial competition game, two identical vendors compete solely by choosing locations along a line.
  2. Any off-center or symmetric split lets one player profitably deviate inward to capture over half the market.
  3. Both players converging on the exact midpoint is the unique Nash equilibrium, explaining the Median Voter Theorem.
Hotelling's GameMedian Voter TheoremNash EquilibriumProfitable DeviationSpatial Competition