2048 — AI Solver
A fully playable 2048 with a built-in AI Hint and Auto-Play solver — drops straight into any page.
Open the full 2048 AI Solver · Open the widget · Setup guide
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Free Widgets for Your Website
Drop any of these LK Forge tools onto your own site with a single line of code — no signup, no fees, nothing to install. Copy the iframe, paste it in, done. Keep the small credit link and the widget stays free forever.
Games
24Tic-Tac-Toe — Unbeatable AI
A tic-tac-toe game against a real minimax AI — provably unbeatable on 3×3, winnable on larger boards up to 10×10.
Open the full Unbeatable Tic-Tac-Toe AI · Open the widget · Setup guide
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Chess — vs AI Engine
A full chess game against a real client-side engine — three levels, legal-move highlights, move list, undo, hints and pass-and-play.
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Go (Weiqi / Baduk) — vs AI
Play Go against a Monte-Carlo search engine on 9×9, 13×13 or 19×19 — with captures, ko, territory scoring and a hint button.
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Texas Hold'em — vs AI (play-money)
Heads-up no-limit Texas Hold’em against an equity-aware AI — play-money, with live win-odds and difficulty levels. No real gambling.
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Backgammon — vs AI
Full backgammon against a computer opponent — dice, doubling, the bar and bear-off, with legal-move highlights.
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Hearts — vs AI
The 4-player trick-taking card classic against three AI opponents — passing, the queen of spades and shooting the moon.
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Euchre — vs AI
Partnership euchre against AI — bidding, trump, going alone and the full 10-point game.
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Bridge Bidding — SAYC
Practice bridge bidding — bid a full SAYC auction against the computer, which explains every call.
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Mancala — vs AI
Kalah-rules mancala against a search-based AI — sow, capture, earn extra turns and bear off to your store.
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Crazy Eights — vs AI
The shedding card game against AI — match rank or suit, play an eight to change the suit, first to empty a hand wins.
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Solitaire (Klondike)
Classic Klondike solitaire with drag-and-drop, draw-1 or draw-3, undo and auto-move to the foundations.
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Mahjong Solitaire
Tile-matching mahjong solitaire — clear the layout by pairing free tiles, with hints, shuffle and undo.
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Memory Match
The concentration card game — flip and match pairs, pick the grid size, with move and timer counters.
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AI Snake
Classic Snake with a real pathfinding autopilot — watch a breadth-first search or a Hamiltonian cycle fill the board.
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Hangman
The word-guessing classic — pick a letter before the drawing completes, across several word categories.
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Color Lines
The classic 9×9 Color Lines puzzle — move balls to build lines of five same-colour marbles and clear the board.
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Rubik's Cube Solver
Paint your scrambled cube and watch a step-by-step animated solution, or scramble and solve it yourself.
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Rubik's Cube Timer
A WCA-style speedcuber timer: hold to ready, release to start, with random scrambles and live best, mean, ao5 and ao12 stats saved in the browser.
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Minesweeper — vs AI board
The classic Minesweeper with adjustable difficulty, a no-guess fair-board option and a hint that flags a safe square. No sign-up.
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Sudoku
A full Sudoku with four difficulties, pencil-mark notes, hints and a timer — puzzles generated fresh in the browser, no sign-up.
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Connect 4 — vs AI
Drop discs against a real bitboard AI with three difficulty levels — the classic four-in-a-row, with undo and a running score.
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Checkers — vs AI
Play checkers (draughts) against a real search-engine AI — three levels, hints, undo and move analysis.
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Othello / Reversi — vs AI
Play Othello / Reversi against a negamax AI — legal-move hints, live disc counts, three difficulty levels and undo.
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Solvers
8Sudoku Solver
Type in any Sudoku and get the unique solution instantly — the solver’s fill shown in colour, all in the browser.
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Chess Solver
Set up a position or paste a FEN and get the best move, principal line and forced-mate detection from a client-side engine.
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Connect 4 Solver
Set up any Connect 4 position and get the perfect move from a solved-game engine, with a win/loss/draw verdict.
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Minesweeper Solver
Enter a Minesweeper board and get the guaranteed-safe squares and a mine probability for every unknown cell.
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Tic-Tac-Toe Solver
Enter any tic-tac-toe position and get the optimal move and the outcome with perfect play.
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Crossword Solver
Enter a pattern like c_o___o_d and find every matching word, with an optional “also contains” filter.
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Sliding Puzzle Solver
Enter an 8- or 15-puzzle and get an optimal step-by-step solution via IDA* search.
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Maze Solver
Generate or draw a maze and watch it solved with the shortest path highlighted.
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Physics
52Particle Collider Simulator
Accelerate electrons and positrons, smash them head-on, and watch the tracks curve in a detector — slide the energy to 91 GeV to light up a Z⁰ boson. Runs entirely in the browser.
Open the full Particle Collider Simulator · Open the widget · Setup guide
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Simple Pendulum Simulator
Release a single bob and watch it swing and trace its arc — drag to set the angle, change the length and gravity, and compare the measured period with the ideal T = 2π√(L/g). Runs entirely in the browser.
Open the full Simple Pendulum Simulator · Open the widget · Setup guide
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Photoelectric Effect Simulator
Shine light on a metal and watch electrons fly off — but only above a threshold frequency. Change the wavelength, intensity, metal and stopping voltage, and read Planck's constant off the KEmax-versus-frequency line. Runs entirely in the browser.
Open the full Photoelectric Effect Simulator · Open the widget · Setup guide
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Free Body Diagram Maker
Load a scenario or add your own force arrows to a body, drag each arrowhead to change its size and direction, and read the net force, whether it is in equilibrium, and the acceleration a = Fnet/m. Runs entirely in the browser.
Open the full Free Body Diagram Maker · Open the widget · Setup guide
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Bohr Model of Hydrogen
Move an electron between hydrogen energy levels and watch it emit a photon of the right colour as it falls, building the Lyman, Balmer and Paschen emission series on a spectrum. Runs entirely in the browser.
Open the full Bohr Model of Hydrogen · Open the widget · Setup guide
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Ideal Gas Law Simulator
A gas-in-a-box where particles bounce off the walls: change the number of particles, the temperature and the volume, and watch pressure respond while PV/NT stays constant. Runs entirely in the browser.
Open the full Ideal Gas Law Simulator · Open the widget · Setup guide
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Doppler Effect Simulator
A moving source emits circular wavefronts that bunch up ahead and stretch behind; change the speed and frequency to read the pitch shift, and reach Mach 1 for a shock wave. Runs entirely in the browser.
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Refraction & Snell's Law Simulator
Send a ray across the boundary between two media and watch it bend by Snell's law; change the incidence angle and the refractive indices, and past the critical angle find total internal reflection. Runs entirely in the browser.
Open the full Refraction & Snell's Law Simulator · Open the widget · Setup guide
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Geometric Optics Ray Diagram Simulator
Draw ray diagrams for converging and diverging lenses and for concave and convex mirrors; drag the object and trace the three principal rays to the image, with live image distance, magnification and type. Runs entirely in the browser.
Open the full Geometric Optics: Ray Diagram Simulator · Open the widget · Setup guide
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Prism Light Dispersion Simulator
Send white light through a triangular prism and watch it disperse into a rainbow via wavelength-dependent refraction. Adjust the apex and incidence angles, switch crown glass for flint or water, and read deviation, minimum deviation and total internal reflection live.
Open the full Prism Light Dispersion Simulator · Open the widget · Setup guide
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States of Matter Simulation
Heat a box of atoms and watch it melt and boil: a real Lennard-Jones molecular-dynamics sim where cooling locks a solid crystal, warming makes a flowing liquid, and more heat boils a gas, with live temperature and phase. Runs entirely in the browser.
Open the full States of Matter Simulation · Open the widget · Setup guide
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Electromagnetic Induction Simulator
Push a magnet through a coil and watch Faraday's law induce a voltage as the flux changes; the galvanometer needle flips direction as the magnet passes through, and speed and turns raise the EMF. Runs entirely in the browser.
Open the full Electromagnetic Induction Simulator · Open the widget · Setup guide
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Radioactive Decay & Half-Life Simulator
Watch a population of nuclei decay at random, one by one, while the survivor count traces the exponential half-life curve N = N₀·2^(−t/t½) against a dashed ideal overlay. Runs entirely in the browser.
Open the full Radioactive Decay & Half-Life Simulator · Open the widget · Setup guide
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Quantum Tunneling Simulator
Fire a particle at a barrier taller than its energy and watch the wave function decay through it and emerge on the far side; the exact transmission probability updates as you change the energy, height and width. Runs entirely in the browser.
Open the full Quantum Tunneling Simulator · Open the widget · Setup guide
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Carnot Cycle Simulator
Watch an ideal heat engine trace the four reversible Carnot steps on a live PV diagram whose enclosed area is the net work, and read the efficiency η = 1 − Tc/Th as you change the reservoir temperatures. Runs entirely in the browser.
Open the full Carnot Cycle Simulator · Open the widget · Setup guide
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Buoyancy Simulator
Drop a block into a fluid and watch it float or sink by density; the buoyant force equals the weight of the fluid displaced, and a floating block settles at a submerged fraction of ρ_object/ρ_fluid. Runs entirely in the browser.
Open the full Buoyancy Simulator · Open the widget · Setup guide
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4-Stroke Engine Simulator
Watch a piston cycle through intake, compression, power and exhaust with the valves and spark animated, beside the Otto-cycle PV diagram; the ideal thermal efficiency η = 1 − 1/r^(γ−1) climbs as you raise the compression ratio. Runs entirely in the browser.
Open the full 4-Stroke Engine Simulator · Open the widget · Setup guide
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Centripetal Force Simulator
Swing a mass in a circle, set mass/radius/speed, and read F = mv²/r, acceleration, angular speed and period live; the force arrow points to the centre, the velocity along the tangent, and cutting the string sends it off tangentially. Runs entirely in the browser.
Open the full Centripetal Force Simulator · Open the widget · Setup guide
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Torque & Beam Balance Simulator
Place a weight on each side of a balance beam and see the moment τ = m·g·d; the lever tips toward the larger torque and sits level when m_L·d_L = m_R·d_R, so a light mass far out balances a heavy one close in. Runs entirely in the browser.
Open the full Torque & Beam Balance Simulator · Open the widget · Setup guide
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Hooke's Law Simulator
Hang a mass on a spring and watch it stretch by x = mg/k (F = kx); a ruler marks the extension while a live force-versus-extension graph draws the straight line whose slope is the spring constant k. Reads the force and elastic energy too. Runs entirely in the browser.
Open the full Hooke's Law Simulator · Open the widget · Setup guide
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Coulomb's Law Simulator
Set two point charges and their separation and see the electrostatic force F = k·q₁·q₂/r² drawn as equal-and-opposite arrows — attracting for opposite signs, repelling for like — with the inverse-square fall-off as you slide them apart. Runs entirely in the browser.
Open the full Coulomb's Law Simulator · Open the widget · Setup guide
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Circuit Simulator (Ohm's Law)
Wire a battery to three resistors in series or parallel and watch Ohm's law V = I·R solve the circuit: total resistance, current, per-resistor voltage/current and power, with current animated as flow along the wires. Runs entirely in the browser.
Open the full Circuit Simulator · Open the widget · Setup guide
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RC & RL Circuit Simulator
Watch a capacitor (RC) or inductor (RL) charge and discharge along the exponential curve set by the time constant τ = RC or L/R; the graph auto-cycles charge → discharge and marks the 63% / 37% point at t = τ. Runs entirely in the browser.
Open the full RC & RL Circuit Simulator · Open the widget · Setup guide
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Logic Gate Simulator
Toggle binary inputs through the seven basic gates — AND, OR, NOT, NAND, NOR, XOR, XNOR — and watch the gate symbol light its wires for logic 1 beside the live truth table with the current row highlighted. Exact boolean logic, runs entirely in the browser.
Open the full Logic Gate Simulator · Open the widget · Setup guide
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Inclined Plane Simulator
Rest a block on a ramp and split gravity into components; change the angle and friction and watch it hold or slide at a = g(sinθ − μcosθ), with the weight, normal and friction arrows drawn. Runs entirely in the browser.
Open the full Inclined Plane Simulator · Open the widget · Setup guide
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Black Hole Simulator
An illustrative view of a black hole: a dark event horizon, a bright photon ring, and a Doppler-beamed accretion disk, with the Schwarzschild radius, photon sphere and ISCO shown for any mass. Runs entirely in the browser.
Open the full Black Hole Simulator · Open the widget · Setup guide
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Double Pendulum
Set two coupled pendulums swinging into deterministic chaos — drag a bob to start, turn on the fading trail, and launch a "chaos twin" a hair apart to watch the two paths diverge. Runs entirely in the browser.
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Simple Harmonic Motion
Release a mass on a spring or a pendulum and watch it draw its own sine wave, trade kinetic and potential energy back and forth, and reveal where "simple" breaks down. Runs entirely in the browser.
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Gravity Simulator
Load the Sun–Earth–Moon, a binary star or the chaotic three-body problem, then fling in new planets and watch their orbits and trails. Runs entirely in the browser.
Open the full Gravity Simulator · Open the widget · Setup guide
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Wave on a String
Send a pulse down a string and watch it reflect — inverted at a fixed end, upright at a free one — or drive the end steadily into a standing wave. Runs entirely in the browser.
Open the full Wave on a String · Open the widget · Setup guide
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Double-Slit Experiment
Fire waves or single photons through two slits and watch interference fringes build up dot by dot — then close a slit and watch them vanish. Runs entirely in the browser.
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Lorenz Attractor
The butterfly of chaos theory in rotatable 3D — a trajectory that never repeats yet stays on the same strange surface; nudge the start and watch two twins diverge. Runs entirely in the browser.
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Bifurcation Diagram
Sweep the logistic map’s growth rate and watch one value split — 2, 4, 8 — into the period-doubling cascade, then zoom into the fractal. Runs entirely in the browser.
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Reaction-Diffusion
Two diffusing chemicals react to paint spots, stripes, mazes and coral — Turing’s mechanism behind leopard spots and seashells. Paint your own. Runs entirely in the browser.
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Conway's Game of Life
The famous cellular-automaton sandbox — draw cells or drop in gliders, guns and oscillators, then watch complex patterns evolve from four simple rules. Runs entirely in the browser.
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Fluid Simulation
Stir a real-time fluid with your mouse — a stable Navier–Stokes solver swirls dye and velocity across the grid. Runs entirely in the browser.
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Charged Particle in a Magnetic Field
Watch a charge circle in a magnetic field and drift under crossed fields, then switch to dipole mode where particles spiral to the poles as the aurora. Runs entirely in the browser.
Open the full Charged Particle in a Magnetic Field · Open the widget · Setup guide
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Projectile Motion Simulator
Launch a projectile and watch its parabola — set the angle, speed and gravity, toggle air resistance, and read off the range, max height and flight time, or drag on the canvas to aim. Runs entirely in the browser.
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Collision Simulator
Fire two carts together and watch momentum and energy trade hands — set the masses, speeds and elasticity, from a perfectly elastic bounce to a dead-stop stick, and see momentum stay conserved. Runs entirely in the browser.
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Electric Field Simulator
Drop positive and negative point charges and watch the electric field appear as field lines or vectors — drag charges to reshape it and see it point away from + and into −. Runs entirely in the browser.
Open the full Electric Field Simulator · Open the widget · Setup guide
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Wind Turbine Energy Lab
Play a day of wind and watch a turbine turn it into electricity — set the wind, rotor size and drivetrain, see the Betz limit cap the capture at 59.3%, and track the battery charging through the day. Runs entirely in the browser.
Open the full Wind Turbine Energy Lab · Open the widget · Setup guide
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Solar Panel Energy Lab
Run a day of sunlight on a tilted solar panel — change the tilt, latitude and date, watch the sun arc overhead, and see how much of the Shockley–Queisser ceiling the panel actually captures. Runs entirely in the browser.
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Nuclear Energy Lab
Operate a nuclear plant and trip a SCRAM — watch the Carnot limit cap efficiency near one third, two-thirds leave as waste heat, and the unavoidable decay heat that must still be cooled after shutdown. Runs entirely in the browser.
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Geothermal Energy Lab
Draw power from a hot underground reservoir over decades — set the flow, temperature and reinjection, and watch the reservoir cool and the output fade when you extract faster than it recharges. Runs entirely in the browser.
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Battery Storage Lab
Charge and discharge a lithium-ion battery — set the C-rate, depth of discharge and temperature, and watch the round-trip efficiency, heat and capacity fade over cycles. Runs entirely in the browser.
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Pumped Hydro Storage Lab
Pump water uphill to store energy, then run it back down through the turbine — set the head and flow, and watch friction, evaporation and turbine losses set the round-trip efficiency. Runs entirely in the browser.
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Flywheel Energy Storage Lab
Spin up a flywheel to store energy, hold it, then draw it back — great for a fast burst, but watch the standby losses bleed it away in hours. Runs entirely in the browser.
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Hydrogen Energy Storage Lab
Store energy as hydrogen — electrolyze, hold for days almost loss-free, then run a fuel cell — and see why the round-trip is low but the holding time is seasonal. Runs entirely in the browser.
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Rocket Launch Lab
Launch a rocket and watch the Tsiolkovsky Δv ceiling meet reality — set Isp, mass ratio and thrust-to-weight, and see gravity, drag and steering losses eat into the ideal Δv. Runs entirely in the browser.
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Jet Engine Lab
Run a turbofan across its flight envelope — set the bypass ratio, pressure ratio and speed, and watch thermal and propulsive efficiency trade off into overall efficiency and thrust. Runs entirely in the browser.
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Ion Thruster Lab
Fly an ion-thruster mission — set the beam voltage and propellant, and watch the Isp-versus-thrust tradeoff and the slow Δv build-up over hundreds of days. Runs entirely in the browser.
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Propeller Lab
Turn shaft power into thrust with a propeller — set the diameter, RPM and airspeed, and watch actuator-disk theory trade induced, profile and swirl losses while the tip speed climbs toward Mach 1. Runs entirely in the browser.
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Chemistry
4Beer's Law Calculator
Set concentration, path length and molar absorptivity and read absorbance and %T from A = ε·b·c live; then add stray light and a polychromatic beam to watch the calibration curve bend away from the straight Beer's-law line. Runs entirely in the browser.
Open the full Beer's Law Calculator · Open the widget · Setup guide
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Photometric Error & Optimal Absorbance
Plot the relative concentration error against absorbance for the detector-, shot- and source-flicker-noise regimes and find the optimal-absorbance minimum near A ≈ 0.4 that tells you where to measure. Runs entirely in the browser.
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Calibration Methods (Standard Addition)
Compare the external-standard and standard-addition methods on one plot: fit a least-squares line to standards, recover an unknown, and dial in a matrix effect to watch external calibration go biased while standard addition still lands on the true value. Runs entirely in the browser.
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Transmission Fitting (TFit)
Compare simple absorption, single-wavelength log absorbance, CLS regression and TFit across a 10,000× absorbance range, and see why fitting the instrument-broadened transmission model (TFit) stays hyperlinear where log(Io/I) rolls off. Runs entirely in the browser.
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Music
10Tone Generator
Play any frequency from 20 Hz to 20 kHz with sine, square, sawtooth or triangle waves, snap to the nearest note, and try binaural beats — generated live in the browser.
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Online Metronome
A precise online metronome — set the tempo with a slider or tap tempo, watch the pendulum and beat lights, and pick the sound. For practice and lessons.
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Guitar Tuner
Tune by microphone with a live needle and cents readout, or by ear with reference tones — Standard, Drop D, Half-step, Open G and DADGAD. Nothing is uploaded.
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Ukulele Tuner
Tune by microphone with a live needle and cents readout, or by ear with reference tones — Standard gCEA, Low G, Baritone and D-tuning. Nothing is uploaded.
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Online Synthesizer
A playable browser synth — oscillator, envelope and effects, a live scope, and presets. Play with the mouse or your keyboard.
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Online Piano
A playable browser piano — mouse or computer keyboard, selectable sound, octave shift and note labels.
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Drum Machine
A step-sequencer beat maker — build patterns, set tempo and swing, and play them back in the browser.
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Circle of Fifths
An interactive circle of fifths — click any key for its signature, notes, chords and relative minor.
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Chord Finder
Build a chord from a root and quality, or name a chord from notes you pick on the keyboard — with playback.
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BPM Counter
Tap along to any track and read the tempo in BPM, with note-delay and beat reference tables.
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Quizzes
4Love Language Quiz
30 quick either/or questions reveal a visitor’s love language — words, acts, gifts, quality time or touch — with a percentage breakdown and a shareable result. Free, no sign-up, no email.
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Attachment Style Quiz
A 30-question quiz that scores secure, anxious, avoidant or disorganized attachment, with an instant breakdown. Free, no sign-up, no email.
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Enneagram Test
A 36-question Enneagram test that reveals a visitor’s type from the Reformer to the Peacemaker, with a wing hint. Free, no sign-up, no email.
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Big Five Personality Test
The science-based 50-item IPIP Big Five — scores Openness, Conscientiousness, Extraversion, Agreeableness and Neuroticism with an instant profile. Free, no sign-up, no email.
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Education
6Spin the Wheel
A random picker wheel — preload your own options and let visitors spin for a winner.
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Word Unscrambler
A full word unscrambler and anagram solver — optionally preload letters with ?q=.
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Word Search Solver
Paste a word-search grid and a word list, then highlight every hidden word — forwards, backwards and diagonal. Runs entirely in the browser.
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Random Word Generator
Generate random words with filters for type, length and syllables — for writing prompts, games and brainstorms.
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Game AI Visualizer
Watch the three classic algorithms behind LK Forge’s games run live: minimax with alpha-beta pruning on Tic-Tac-Toe, expectimax averaging over a chance node, and breadth-first search finding a shortest path. Runs entirely in the browser.
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Pathfinding Visualizer
Draw a grid with walls and weighted cells, then watch BFS, Dijkstra and A* search for the shortest path — and compare how many cells each explores. The classic demo of why A*’s heuristic wins. Runs entirely in the browser.
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Math
2Polygon Area Calculator
Find the area of any polygon — from vertex coordinates (shoelace), a triangle’s three sides (Heron), or a regular polygon’s side — with a labelled diagram and worked steps.
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Percentage Calculator
Work out any percentage — X% of Y, what percent X is of Y, or a percentage change — with a worked explanation.
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Calculators
3Mortgage Calculator
Estimate a monthly mortgage payment with total interest and a full amortization schedule and chart.
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Tip Calculator
Split a bill and work out the tip — set the percentage and number of people for a per-person total.
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Age Calculator
Find an exact age in years, months and days between any two dates — plus total weeks, days and hours.
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Health
5Body Fat Calculator
Estimate body fat from tape measurements (U.S. Navy method) or from BMI — with category, fat mass and lean mass.
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BMI Calculator
Find your Body Mass Index from height and weight (metric or imperial), with your category on a colour scale.
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BMR Calculator
Estimate your basal metabolic rate — the calories you burn at rest — from age, sex, height and weight.
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Due Date Calculator
Estimate a pregnancy due date from the last period, conception or IVF transfer, with key milestones.
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Ideal Weight Calculator
Find a healthy weight range for your height and sex across the Devine, Robinson, Miller and Hamwi formulas.
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Design
5Pixel Art Editor
A grid-based pixel-art and sprite editor — draw, fill, pick colours and export a scaled PNG, all in the browser.
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Whiteboard
A pannable, zoomable whiteboard — sketch freehand, drop shapes, arrows, sticky notes and text, then export.
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Drawing Tool
A freehand drawing canvas with shapes, colours, layers and stamps — export to PNG, SVG or a project file.
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Wireframe Tool
Build low-fi UI wireframes from ready-made components on a snapping canvas — layers, alignment and export.
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Flowchart Maker
Draw flowcharts and diagrams — shapes, connectors and templates on a snapping canvas, with export.
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Live data
13Air Quality (AQI)
Live air quality index (AQI) for any city — PM2.5, PM10, ozone and more, with plain-English health guidance. Pin it to your city with ?place=London.
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Pollen Forecast
Today's pollen levels for any European city — grass, birch, ragweed and more, with allergy guidance. Pin it to your city with ?place=Berlin. Europe only.
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Tide Times
Today's high and low tide times for any US coast — the next tide, a tide chart and heights, from the nearest NOAA station. Pin it with ?place=Boston. US only.
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Rocket Launch Tracker
The upcoming orbital rocket launch schedule — SpaceX, NASA, ULA and more — with a live countdown to the next liftoff, from Launch Library 2.
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Satellite Tracker
Live positions of well-known satellites — the ISS, Hubble, Tiangong and more — on a world map, with altitude, speed and ground tracks. Pin one with ?sat=hubble. Orbits computed in the browser from CelesTrak data.
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Space Weather
Live space weather from NOAA SWPC — the R/S/G storm scales, Kp index, solar wind and recent solar flares, auto-refreshing. A dashboard of current conditions in near-Earth space.
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Earthquake Tracker
A live map and list of recent earthquakes worldwide, straight from the USGS feeds. Pin it with ?place=Tokyo or ?region=Japan (trim to a radius with ?maxdist=200), preset filters with ?mag=4.5, ?period=week and ?units=mi, and match your site’s theme with ?theme=dark.
Open the full Earthquake Tracker · Open the widget · Setup guide
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ISS Tracker
The International Space Station’s live position on a world map, with altitude and speed, refreshed every few seconds.
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Aurora Forecast
A live aurora probability map and Kp index from NOAA SWPC — see how far south the northern lights may be visible tonight.
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Asteroid Tracker
Near-Earth asteroids making close approaches, from NASA/JPL — size, speed and miss distance in lunar distances.
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Moon Phase
Tonight’s moon phase and illumination, the next full and new moon, and a 30-day calendar — runs offline in the browser.
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Sun Times
Sunrise, sunset, solar noon, golden hour and day length for any place and date, plus the solstices and equinoxes.
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Atmospheric CO₂
The latest atmospheric CO₂ level and its long-term trend, from official NOAA records — a citable live chart.
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Productivity
1World Clock
A live multi-city clock — set cities with ?cities= and match your theme with ?theme=dark.
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Utilities
5White Screen & Colour Screen Test
A full-screen white screen in one click — a clean lightbox, video-call fill light and the fastest way to spot dust and dead pixels, plus black, red, green, blue and grey.
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Reaction Time Test
Wait for the pad to turn green, then click as fast as you can — measures reaction speed in milliseconds over five rounds, shows the average and best and saves a personal best. Free, no sign-up.
Open the full Reaction Time Test · Open the widget · Setup guide
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Gamepad Tester
Connect any controller and watch every button, trigger and analog stick respond live, with exact axis values to check for stick drift. Works with Xbox, PlayStation, Switch Pro and USB pads.
Open the full Gamepad Tester · Open the widget · Setup guide
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Mouse Test
Check every mouse button and the scroll wheel, catch double-click faults from a worn switch, and measure your mouse polling rate in Hz — all live in the browser. Free, no sign-up.
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Typing Speed Test
A one-minute typing speed test — type the passage and get live WPM and accuracy. For practice, keyboarding lessons and quick challenges.
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Randomizers
3Coin Flip
A cryptographically fair heads-or-tails coin flip with a flip animation, a running tally, batch flips and custom labels — for classrooms, giveaways and quick decisions.
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Dice Roller
Roll d4–d100 with a dice count and modifier, real pips for six-sided dice, and a running total — for tabletop games and classroom picks.
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Random Number Generator
Generate random numbers in any range, with a no-duplicates mode and optional sorting — for raffles, giveaways and fair picks.
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Free to use anywhere. These widgets are free for any website, personal or commercial. The only ask is that you keep the visible credit link beneath each embed — that link is what keeps them free. Widgets load lazily and run entirely in the visitor's browser. Need help placing one? Each has a step-by-step setup guide.