SpecEnvoy Learn
Small, free, playful tools that help anyone actually learn — not just drill. Everything we've built is listed below, by subject. Works on any phone, nothing to install, nothing tracked.
Looking for something specific? Every tool is on this page — scan the subject you want, or search from the header (/ / ⌘K). Why we're building this →
Spotlight · advancedFourierBuild waves, watch epicycles draw them — the Fourier transform as geometry
Arithmetic TrainerTimes tables by heart — learn, flashcards, quiz
FunctionsLines & systems, transform parent graphs, parabolas, polynomials, exp & log
Trigonometry PlaygroundDrag-the-angle demos for sin, cos, tan & the sine/cosine rules
CalculusLimits, derivatives & integrals you can see — secants, tangents, Riemann sums
VectorsMagnitude, direction & the dot product
Linear AlgebraMatrix transformations, the complex plane & the cross product
Statistics & ProbabilityTree diagrams, the normal curve & the line of best fit
SpotlightInstruments Through TimeTimelines of the cello, violin, piano, flute & clarinet — composers, portraits & playable scores
Music TheoryHarmony & analysis — the circle of fifths, chords, cadences, Roman numerals (Level 9 & 10)
Practice StudioDrone, metronome & tuner in your browser
Sight-Reading TrainerName the note — bass, tenor & treble clef
The Language of MusicAn interactive primer on the terms & symbols
Play with ScoreEvery playable piece, following the notation
String Quartets364 movements — Haydn to Debussy, all four instruments playing together
Songs486 songs — Schubert's Ave Maria and Ständchen to Wolf, the melody follows while the piano plays
Hymns19 classics — Amazing Grace to Silent Night, four-part settings on piano
The MakersAmati to Vuillaume, school by school, with the Met's photographs
SpotlightThe ElementsTap any of 118 elements — watch the atom spin, see how it powers the modern economy
Atom BuilderAdd protons, neutrons & electrons — build any atom, isotope or ion with a live Bohr model
Molecule LabSpin real molecules in 3D — VSEPR shapes, bond angles & polarity, from public-domain data
Gas & States LabA live particle box: the gas laws (PV=nRT) and melting/boiling, animated
Equation BalancerBalance reactions, watch atoms conserved, and learn the five reaction types
SpotlightThe Human Body in 3DOrbit a semi-transparent body, tap any organ for what it does + a clinical fact that sticks
How Your Body WorksSystems in action, in real 3D — a beating heart, breathing lungs, with live rates as you rest or sprint
The Journey of a MealEat and follow a bite through the gut — the real timing at every stop
What's in Your FoodBuild a plate and see calories, protein, carbs, fat & fibre add up
Your Energy BudgetHow many calories you burn a day and where they go
Muscles & MovementBend an elbow and watch biceps and triceps trade off — why a muscle can only pull
Joints & Range of MotionThe six kinds of joint — move each one to its real limit, in degrees
Your SensesPlay a real tone to the edge of your hearing, then focus an eye near and far
First Aid BasicsA CPR-rhythm trainer + the essentials (Red Cross / AHA)
Teeth & DentalAn interactive chart of all 32 adult teeth + a labelled cross-section of a tooth
DNA & InheritanceA 3D double helix + Punnett squares — how traits pass from parents to children
Understanding CancerSee the organ where each common cancer begins, in 3D — what it is, its signs, and how it's treated
Test YourselfA quick body quiz — name the organ, its system and its job, plus fun facts
Space
your place in the galaxy
RebuiltLearn 中文 ChineseImport the weekly class worksheet — eight tools practice exactly its lesson
Import a Lesson 导入Worksheet PDF or photo → characters, word families, poem & reading, ready to practice
认字 Word FamiliesEach character through its 组词 family, with smart review cards
拼音 QuizType the pinyin, tones included — plus a tone-ear game
写字 Writing & 听写Stroke order in a 田字格: watch, trace, write from memory, dictation
造句 SentencesUnscramble the lesson's sentences; learn its 成语
古诗 PoemsRead along, fill blanks, recite — record yourself
朗读 Read-AloudThe 课文 with line audio and a mic check on Chrome
Progress 进度Characters known, streak, what to review today
Puzzles
train your brain, hands onGame craft
how games get made — taught from our own bugsMore subjects and tools on the way.