Mr. Grummel Early access
MR. GRUMMEL  /  PERIOD 1

The app blocker that teaches you something.

Open a blocked app and Mr. Grummel steps in. Answer his three questions right and you earn your phone back — plus three facts you'll actually keep.

Get early access Take his quiz →
NO PHONES
IN CLASS
Mr. Grummel — your new screen-time teacher
LESSON PLAN

Cognitive friction, not punishment.

STEP 01
You open a blocked app
Mr. Grummel intercepts the launch. Instead of a grey wall, you get a classroom — and a teacher who has been waiting.
STEP 02
Mr. Grummel writes the questions
Three questions from your chosen curriculum, chalked out one at a time. Get them right and the app opens. Get them wrong and he has notes.
STEP 03
The streak keeps you honest
Three phones on the paper, a daily learning streak, and accuracy you can watch climb. Friction that compounds into knowledge.
POP QUIZ — TRY IT
QUESTION #1

What is 8 × 7?

Well? I have all period.

Streak
THE CURRICULUM

Real subjects. Thousands of questions.

17 subjects, each broken into domains and topics in one connected knowledge tree. Every unlock pulls the next question from where you actually are — no random trivia pile.

Mathematics 7 DOMAINS

Numbers, structures, spaces, and change

Arithmetic Algebra Geometry Trigonometry Calculus Statistics Discrete Mathematics
Physics 5 DOMAINS

The fundamental laws of the universe

Mechanics Thermodynamics Electromagnetism Waves & Optics Modern Physics
Chemistry 6 DOMAINS

Matter, its properties, and reactions

General Organic Inorganic Physical Analytical Biochemistry
Biology 6 DOMAINS

Life and living organisms

Cell Biology Genetics Evolution Ecology Human Biology Microbiology
Computer Science 7 DOMAINS

Computation, algorithms, and digital systems

Programming Algorithms Data Structures Databases Networking AI/ML Cybersecurity
History 7 DOMAINS

The record of past human events

Ancient Medieval Early Modern Modern Contemporary Cultural Economic
Geography 5 DOMAINS

Earth's landscapes, environments, and peoples

Physical Human Geopolitics Environmental World Capitals
Philosophy 5 DOMAINS

Fundamental questions of existence and knowledge

Metaphysics Ethics Logic Epistemology Political Philosophy
Literature 5 DOMAINS

Written works and the art of language

Poetry Fiction Drama Literary Analysis Rhetoric
Art 5 DOMAINS

Visual creation and aesthetic expression

Drawing Painting Sculpture Design Art History
Music 4 DOMAINS

Sound, rhythm, and musical expression

Music Theory Composition Performance Music History
Economics 5 DOMAINS

Production, distribution, and consumption of goods

Microeconomics Macroeconomics Trade Finance Behavioral Economics
Psychology 4 DOMAINS

The human mind and behaviour

Cognitive Behavioral Developmental Neuroscience
Sociology 4 DOMAINS

Human society and social behaviour

Culture Institutions Social Theory Demographics
Engineering 4 DOMAINS

Application of science to design and build

Mechanical Electrical Civil Chemical
Medicine 4 DOMAINS

The science and practice of healing

Anatomy Physiology Pathology Pharmacology
Business 4 DOMAINS

Commerce, organisations, and value creation

Accounting Marketing Management Entrepreneurship
MISSING SOMETHING?

Put it on the syllabus.

Tell us the subject or topic you want to be quizzed on. Requests with the most votes get written into the curriculum first.

TOPIC REQUEST SLIP

From the staff room.

All notes →
BEHIND THE APP
Why we chose quizzes over push-ups
Physical friction costs you the room. Cognitive friction costs you a few minutes and pays you back three facts.
LEARNING
Spacing, streaks and the forgetting curve
How the question scheduler decides what Mr. Grummel asks you next — and when he asks it again.
PRODUCT
Building a classroom that fits in an intercept screen
Notes on animating a teacher who has to load in under 300ms, twenty times a day.
REPORT CARD
$4.99 a month.
7 days free.
Cancel any time — the facts you learned are yours to keep.
iPhone first. Android right behind it.