learning

Interactive reference where every CSS selector is demonstrated live against a sample DOM you can modify.

Browser game with 24 levels where you write flexbox properties to move frogs onto matching lily pads.

Puzzle game teaching CSS Grid by having you water carrots and poison weeds using grid placement properties.

Two-part article giving concrete visual rules — light source, spacing, contrast, saturation — for developers designing interfaces.

Essay arguing that books are a bad transmission medium for knowledge, and what learning interfaces should do instead.

Thirty-two level game that teaches CSS selectors by asking you to select plates, bento boxes and apples.

Codepip game about CSS transforms, teaching translate, rotate, scale and skew by rearranging scattered objects.

Collection of short lessons on writing CSS that survives long content, missing images, RTL text and unexpected data.

Large collection of annotated Phaser 3 games and mechanics written in TypeScript as learn-by-reading examples.

Experimental mnemonic textbook on quantum computing with spaced-repetition prompts embedded directly into the prose.

Serves a random modern-CSS technique with runnable demo, as a daily learning surface.

Curated syllabus of thirty-three core JavaScript concepts, each with articles, videos and code, translated into forty-plus languages.

Free virtual guitar you strum with your keyboard or fingers, with recorded acoustic, classic, electric and bass samples, 51 slowed-down songs and a backing band.

Read-only TUI that has Claude Code, Codex, Gemini or OpenCode turn a git branch into a step-through tour of intent, risks, questions and verdicts.

Step-by-step animated lessons on system design, networking and computer science where you watch requests move, predict the next step, and break things.

Six free interactive experiments on the assumptions that break software: predict the outcome, break it, repair it, and keep the regression test.

Interactive Scala 3 lessons in the browser with a live Scastie editor on every page and no install or account.

Browser tool for exploring scales, chords and how they combine across guitar, piano, cello and alto recorder with a complexity toggle.

Gallery of 135 live CSS 3D effects with how-it-works notes and paste-anywhere snippets, split into pure CSS versus CSS plus a little JS.

Conway's Game of Life running from a 512-byte x86 boot sector, using VGA memory as the grid, with heavily commented assembly.

Mobile-friendly math practice that builds automaticity on topics you already know, with no account and progress kept on device.

Interactive atlas of system designs with architecture diagrams, trade-off pages and interview playbooks ranked by how often they come up.

Agent skill that turns PDFs, books, and papers into interactive learning webpages with quizzes, notes, and source traceability.

Browser quiz that teaches NYC metro-core neighborhoods by tapping the right place on the map.

MIT TypeScript Live2D viewer with motion controls plus an end-to-end production skill documenting mesh, physics and web interactivity.

Plain-English explainer of everything a single web page can learn about you, with expandable entropy math and no third-party tracking.

Interactive tree of life merging 11 taxonomies with 41 trait overlays — habitat, size, longevity, depth — all with provenance.

Tarot-style card deck where each card carries a GLSL snippet, teaching shader techniques as a physical practice.

Official free learning path covering tweens, easing, staggers, timelines and callbacks with editable inline examples.

Platform for embedding spaced-repetition prompts into web essays so readers retain what they read.

Interactive sandbox exposing every flex container and item property with live layout preview and copyable generated CSS.