learn.

Interactive teaching, owned by everyone.

Small widgets that each make one claim and let you test it with your own hands. AI drafts them, the people who use them refine them, and anyone can use them anywhere, free.

Browse the 39 widgets Use them in your chats

Try one

Doubling ruler On a log-scale ruler equal ratios of x are equal distances, so every ×2 moves the marker one doubling and every ×10 moves it log₂ 10 ≈ 3.32 doublings. Open it and take the check →
Nyquist fold A sinusoid sampled at fₛ keeps its pitch only below the Nyquist frequency fₛ/2; above it the samples are identical to those of a lower sinusoid at |f − fₛ·round(f/fₛ)|, and that alias is what plays back. Open it and take the check →
Biased coin entropy A coin's entropy H(p) = −p log₂ p − (1−p) log₂(1−p) peaks at exactly 1 bit per flip when p = ½ and falls to 0 as the coin becomes certain. Open it and take the check →
Multiply by i Multiplying z by i rotates it a quarter turn counter-clockwise, swapping its coordinates and negating the new real part, so i²z = −z. Open it and take the check →

Five ways to use it

  1. Learn

    Browse the library by topic, or follow a course that puts the widgets in order with the prose between them.

    Browse Courses

  2. Ask in your own chats

    Add the connector and your assistant pulls the right widget into the conversation, or drafts a new one when nothing fits. That draft joins the library for the next person who asks.

    Set it up Try the tutor here

  3. Put one on your page

    Two lines. The widget runs in a sandbox that cannot touch your page, and the library is CC-BY-4.0.

    <script src="https://learn.mimmsy.com/learn-widget.js"></script>
<learn-widget name="logarithms-ruler" check></learn-widget>
    Build a snippet

  4. Keep what you do

    An account puts your name on the widgets you make and keeps what you have checked, on the site and in your chats.

    Sign in

  5. Make it better

    Disagree with a check, propose a link, fork a widget, or send a pull request. Every widget shows who made it and what changed.

    The library on GitHub Why this exists