How this platform works
What is on every lesson page, and how the pieces fit together. Nothing needs an account: your progress lives in this browser.
What things look like
A model scores 99% on training data and 61% on new data. What is happening?
loss = criterion(model(x), y)loss.backward()- Not started
- Started
- Practised
- Mastered
Learn
Work through one section at a time
Each lesson opens with its goal, what you will be able to do by the end, the data it uses and an honest time estimate. The outline on the left lists the sections; each node fills in as you finish reading it or choose Mark section complete. Use the section controls to move forward or back, or choose Show whole lesson for continuous reading. Press F for read mode: the navigation goes away so you can focus on the current section; Esc brings it back. On a phone, the bar at the bottom of a lesson opens the sections and steps between them.
Play with the labs
Labs are live experiments that run in your browser, placed where the idea they show is explained. Some carry a challenge: hit the goal and see where your result sits among everyone who has tried.
Run the code, then write some
Every code cell from the notebook is here with the output it actually produced; numbered markers match line-by-line notes underneath. In the early lessons, Run runs a cell in your browser (the first run loads Python, which takes a few seconds), and the cell’s ⋯ menu lets you edit it and run your version. Exercises ask you to fill in the blanks; Check tests your code, with hints and a solution when you need them.
Look up any term, and see how the ideas connect
Words with a dotted underline have a definition: hover, or tap on a phone. The glossary lists them all, and the concept map shows what each idea builds on and what it leads to.
Practise
Answer the checkpoint at the end of each section
A checkpoint closes every section: a few quick questions with an explanation for each answer. Some ask you to explain an idea in your own words; the tutor reads your answer and tells you what is solid and what is missing. You can move between sections freely. Answering the checkpoint gives you evidence of understanding and builds your review queue.
Think before you look
Question cards in the text ask you to check your understanding, pause and think, or try it yourself. Press Write my answer to jot down your thinking (kept on this device), then Show explanation to compare. The quiz at the end of the lesson draws the threads together.
Come back for a daily review
Every question you answer joins your daily review, which opens straight on the first question due. A miss comes back tomorrow; a right answer comes back after longer and longer gaps: a few days, a week, two weeks, a month, then three months. The number beside Review in the top bar (or the tab bar on a phone) shows how many are due.
Track and carry
Master each lesson, pass each module
A lesson is mastered when you have read it through, answered most of its checkpoints with at least 70% right, and finished its quiz with the same score. The panel at the end of each lesson shows what is left. Each module page ends with a module challenge, one question at a time, that mixes ideas from several lessons. Pass it to earn that module's badge.
Keep a training log
My progress is your training log: how many lessons you have mastered, a weekly goal you set yourself, the days you studied, a skills map of every lesson coloured by strength, your badges and your best lab challenge results. It also says what to do next.
Carry your progress to another device
At the foot of My progress, turn on sync to get a private code. Enter it (or open the link it gives you) on your phone or another computer and your answers, notes, streak and badges follow you. There is no account and no email: whoever has the code has the progress, so keep it to yourself. The tutor key, if you entered one, never leaves the browser it was typed into.
Ask, discuss, and run it for real
Ask the tutor in the top bar answers questions about the lesson you are on. Under every lesson there is a discussion (a GitHub account is needed to post) for questions other learners may share. Every lesson can be downloaded as a notebook from its spine: open it in Jupyter, VS Code or Google Colab, run it, change it. Reading builds understanding; running the code is where it sticks.
Keyboard shortcuts
- ⌘ K or /
- Search lessons, sections and terms
- F
- Read mode on a lesson; Esc leaves it
- Alt ← →
- Previous or next section; in the whole-lesson view, previous or next lesson
- A–D or 1–4
- Answer in the daily review; ↵ for the next question, Esc to stop
- Shift ↵
- Run the cell you are editing
- Esc
- Close search, images and pop-ups
The labs work with the keyboard too: Tab to a control, then use the arrow keys to change it.