# Specification and examples are mutually re-inforcing

What can computers do?
What are the limits of mathematics?
And just how busy can a busy beaver be?
This year, I’m writing **Busy Beavers**,
a unique interactive book on computability theory.
You and I will take a practical and modern approach to answering these questions — or at least learning why some questions are unanswerable!

It’s only $19, and you can get **50% off** if you find the discount code ... Not quite. Hackers use the console!

After months of secret toil,
I and Andrew Carr released **Everyday Data Science**,
a unique interactive online course!
You’ll make the perfect glass of lemonade using Thompson sampling.
You’ll lose weight with differential equations.
And you might just qualify for the Olympics with a bit of statistics!

It’s $29, but you can get **50% off** if you find the discount code ... Not quite. Hackers use the console!

### More by Jim

- Your syntax highlighter is wrong
- Granddad died today
- The Three Ts of Time, Thought and Typing: measuring cost on the web
- I hate telephones
- The sorry state of OpenSSL usability
- The dots do matter: how to scam a Gmail user
- My parents are Flat-Earthers
- How Hacker News stays interesting
- Project C-43: the lost origins of asymmetric crypto
- The hacker hype cycle
- The inception bar: a new phishing method
- Time is running out to catch COVID-19
- A probabilistic pub quiz for nerds
- Smear phishing: a new Android vulnerability

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