How AI Actually Works

Start with a short visual model of LLMs, then go deeper into training, attention, systems, and hands-on practice.

1 Large Language Models Explained Briefly

Start here. This short 3Blue1Brown explainer gives the cleanest first mental model: a chatbot completes a conversation by repeatedly predicting likely next tokens from the current context.

7:58 · 3Blue1Brown · Short visual foundation

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Script completion

A chatbot answer can be framed as completing a dialogue, one token at a time.

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Probability, not certainty

The model scores many possible next tokens, then the system chooses from those scores.

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Sampling creates variety

Allowing less likely tokens can make answers feel natural, but also less repeatable.

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Training shapes behavior

Pretraining learns broad patterns; later feedback helps shape assistant behavior.

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Attention adds context

Attention lets each token draw on the other tokens in its context, weighted by relevance; in chat models, a prediction can never use tokens that come after it.

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2 The $5 Million Reading Game Behind Every AI

Now that you know LLMs predict the next word, where do they learn those patterns? This video shows the pretraining process: how an enormous amount of text gets curated, cleaned, split into tokens, and fed to GPUs for months.

15:53 · Attention Visualized · 3.8K views

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The patient reader

A model that learns by next-token prediction: it covers up the next token (a word or word piece) and guesses it, across its whole tokenized training text.

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Data curation

Most raw web text is filtered out as duplicate, spam, or low quality; only a fraction becomes training text. The exact amounts differ by model.

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Scale

Thousands of GPUs running for months. No teacher — just text.

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3 Self-Attention: How Transformers Actually Work

The deepest dive. Self-attention is the core mechanism that lets each token (a word or word piece) draw on the other tokens in its context, weighted by relevance; in chat models, a prediction can never use tokens that come after it. This is what makes modern AI different from everything that came before.

13:01 · Visual AI · 19K+ views

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Words talk to words

Each token queries the other tokens in its context (in chat models, never later ones) to understand meaning.

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Q, K, V

Query, Key, Value — three projections that compute relevance between words.

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Why it matters

Self-attention solved the long-range dependency problem that held AI back for years.

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4 The Full Picture: From LLM to Agentic Workflow

Now that you understand how LLMs work, see how engineers build real products on top of them. This Stanford course summary covers the full technology stack from base models to multi-agent systems.

Language note: This video is in Chinese (Mandarin). To watch with English subtitles: 1) Click the CC button (bottom-right of the video player) to turn on captions. 2) Click the gear icon (⚙) next to CC. 3) Select Subtitles/CC. 4) Select Auto-translate. 5) Choose English.

27:24 · Gary Chen · 58K+ views · Based on Stanford's "Beyond LLM" course

Topics Covered (English Summary)

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LLM Limitations

No domain knowledge, outdated info, hard to control, struggles with long context.

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Prompt Engineering

A core skill for every AI user. Includes two usage styles: delegating whole tasks vs. collaborating step by step.

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RAG

Retrieval-Augmented Generation — give the model access to your own documents.

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Fine-Tuning

Train the model on your data to specialize it for specific tasks.

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Agentic Workflow

LLMs that can plan, use tools, and take actions — not just answer questions.

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Multi-Agent

Multiple AI agents collaborating on complex tasks, each with a specialized role.

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⚡ Try It Yourself: Train an AI Model

Now that you understand the theory, try training a real AI model yourself. Google's Teachable Machine lets you build an image, sound, or pose classifier in minutes — no coding required. This short video shows how it works in a classroom setting.

5:50 · STEM Learning By Doing · Advanced / Optional

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Train with your data

Collect examples, label them, and watch the model learn the patterns.

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Test and break it

See where the model gets confused — that's how you build intuition for AI limits.

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Try it free

Go to teachablemachine.withgoogle.com and train your own classifier.

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These videos are optional enrichment. You do not need to understand transformer internals to use AI effectively. But knowing what's happening under the hood makes you a sharper, more critical AI user.
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