This is an official ODERSA website. Here’s how you know

The official domain

The address of this site ends in odersa.org. Every service the association runs sits on a subdomain of odersa.org and nowhere else. If the address in your browser’s address bar does not end in odersa.org, this site is not ours.

Free, and no account

Everything is open straight away. No sign-up, no account, no password, no subscription, no advertising. Nothing is held back for those who pay, because there is nothing to pay for.

No data collected

This site does not follow you: no tracker, no tracking cookie, no measurement tool built into these pages, and nothing measured on your device. Our host counts requests in aggregate, as any server that answers does: a total, never a profile. You do not have to take our word for it: open your browser’s developer tools, go to the Network tab, and reload the page. You will see the full list of what the site asks for. Everything comes from odersa.org, nothing goes anywhere else.

Free to reuse

The content is published under the CC BY 4.0 licence. You may copy it, translate it, print it and pass it on, for your classes as much as for the people around you, on one condition only: credit ODERSA.

What these demonstrations show, and what they never settle

Every demonstration is set and rerun on this device, without any artificial intelligence service and without a connection once the page is open. A visible seed makes every result reproducible, and a written method says exactly what the demonstration calculates.

This page gathers 7 demonstrations, one per mechanism in the course. Each one can be set, rerun, and gives a result straight away: none waits for a server, none asks for an account.

The demonstrations

Why everything runs on this device, and why that is not a limitation

No demonstration on this page calls an artificial intelligence service. No key, no account created behind the scenes, not one byte going out once the page is loaded. It is a teaching choice, not a technical retreat.

Information

The trust banner, at the top of this page, already suggests the move: open your browser’s Network tab, use any demonstration above, and watch. No request goes out.

A toy model, here

The corpus fits on the page. The table of counts can be read in full. The formula that turns a count into a probability is one line long, and can be redone by hand. What a demonstration gives back follows from the setting: nothing about it stays mysterious.

An online service, elsewhere

The corpus is closed, the parameters run into billions, and no formula appears next to the answer. Seeing a whole mechanism once teaches you to be wary in the right places about what a black box never shows.

A visible seed, a result that does not change

Every demonstration draws on chance, but never on the opaque chance of the device that opens it. The draw starts from a seed: a word or a number, shown in plain sight, which you can change. Two people who enter the same seed get exactly the same result, on two different devices.

That is what makes a demonstration citable in class and reproducible in a piece of homework. A result that cannot be replayed exactly cannot be checked, and cannot be corrected either.

What none of these demonstrations claims to do

Every demonstration shows a mechanism and names its limits. None goes any further.

What you need to use them

A browser

Nothing to install. Every demonstration runs inside the page, with what the browser already provides.

No account

No sign-up, no password. Nothing identifies whoever is using the demonstration.

No connection, once the page is open

With the page loaded, everything is calculated on the device. A room with no network, or a plane, is enough.

Every demonstration also carries its method, written in plain terms and possible to follow by hand, on paper: the calculation it makes, step by step, up to the result. That is what makes it possible to take it up in class without a screen, or when JavaScript is missing.

Going further

The full course, in its own order, is on the understand page. To prepare a session around these demonstrations, the for teaching path offers an order and a session ready to use as it stands. To copy, translate or print a demonstration, the licence says on what condition.