Labs
Short interactive visualizations you can poke at. Drag something, watch what moves, and build the intuition.
Fitting a Model
Inference: Testing & Estimation
Neural Networks
Neural Networks
A real MLP doing real backpropagation in your browser. One neuron can only draw a line — add a hidden layer and watch the boundary bend around XOR.
- Real backprop
- 3 datasets
- Watch XOR fall
Convolution Kernel
Draw a shape, pick a kernel, and watch the one operation a CNN repeats everywhere. Nine numbers summing to zero turn into an edge detector.
- Draw your own input
- 6 kernels, all editable
- See every multiply
Randomness & Distributions
Distribution Explorer
Drag the parameters and watch the shape, mean, and spread respond. Sweep the plot to read off the probability of landing at or below a point.
- 3 distributions
- PDF & CDF
- Live P(X ≤ x)
Law of Large Numbers
Flip a coin thousands of times and watch the running proportion get reeled in. Chance doesn't correct itself — it gets outvoted by volume.
- 3 processes
- Live simulation
- ±2·sd/√n funnel
Sampling & Central Limit Theorem
Sample a skewed population over and over, average each batch, and watch a bell curve appear from nothing.
- 4 populations
- Live simulation
- n = 1–50
Transformers & Language Models
Tokenization
A real byte-pair tokenizer, trained live on a small corpus. Type “strawberry” and see why a model that writes essays cannot count the r’s in it.
- Real BPE, trained live
- Type anything
- Step the merges
Word Embeddings
Sixteen words plotted as points, where relationships become directions you can do arithmetic with.
- 16 words mapped
- Analogy arithmetic
- See it break
Attention Weights
Click a word and see what it looks at. Real attention over real query and key projections — including the question a single head provably cannot answer.
- Real softmax(QKᵀ/√d)
- Swap the words
- See what it cannot do
RAG Retrieval
Watch a vector search confidently answer a question it has no business answering, then find the cutoff that stops it. This is how RAG fails in production.
- Real cosine search
- top-k vs threshold
- Watch RAG fail
Want the lessons behind them? The Open Library is free to read.