Whetstone
Four papers to sharpen against — Non-Verbal Reasoning, Verbal Reasoning, English and Maths —
for any age from 4 to adult.
Run it
open whetstone/index.html
./serve.sh # local-serviceEvery question is generated
Nothing is drawn from a fixed bank, so it cannot run out and cannot repeat a paper. There are
45 question generators across the four papers, each reading the belt as a difficulty dial.
| Paper | Types | Examples |
|---|---|---|
| Non-Verbal | 5 | odd one out, sequences, rotations, analogies, counting — all drawn as SVG from a shape spec, so puzzles vary one attribute at a time exactly as real NVR does |
| Verbal | 8 | letter sequences, alphabet codes, hidden words, compound words, letters-as-numbers, anagrams, analogies, odd word out |
| English | 7 | spelling, homophones, punctuation, grammar, word classes, plurals, prefixes |
| Maths | 25 | counting → times tables → fractions → percentages → ratio → algebra → equations → nth term → compound interest |
Maths is typed, not multiple choice, with an on-screen keypad — no guessing — and every answer
comes with the working shown.
Age sets the belt
Type an age and the belt follows: *4–6 white, 7–8 yellow, 9–10 orange, 11–12 green, 13–14 blue,
15–16 purple, 17+ black. Nudge it up or down with − / + if it's the wrong fit, and the results
screen offers "try one belt harder"*.
A white belt is never shown algebra; a black belt never gets counting.
Accounts
Make a free account with a username that can only ever be used once. Progress follows the
account to any device. Signing in on a device with more progress than the account asks which to
keep rather than overwriting.
Your password is never stored — only a *PBKDF2-SHA-256 derivation over a random 128-bit salt at
250,000 iterations. Because the store is shared, use a made-up game password you don't use
anywhere else*. No email, no personal details are collected.
A transfer code (Account screen) moves progress by hand, and works offline.