Tools

Dot Cards (Doman) — A tool to teach toddlers numbers using dot cards.

Prime Factorization — An interactive game to practice prime factorization.

Modeling Mixture Problems — Learn to solve mixture problems with an interactive tutorial.

Distributions & Percentiles — Learn how to calculate percentiles and visualize data distributions.

Excel Skills Survey — Self-assess your Excel skills and download a PDF report to share with your manager.

Berkson's Paradox — See how selection bias creates spurious correlations between independent variables.

Galton Board — Visualize publication bias: drop balls through a peg board and see how selecting only significant results distorts the distribution.

Jevons Paradox Simulator — Simulate how efficiency gains can paradoxically increase total resource consumption via the rebound effect.

Investor Game — Single player game to teach kids the Kelly Criterion.

CAASPP Explorer — Explore California standardized test scores by school, district, and demographic group.

School Finder — Find Bay Area private schools by grade, tuition, and location.

SF POPOS Finder — Find San Francisco's privately owned public open spaces, sorted nearest first.

Lyft Bike Finder — Find nearby Lyft bike stations with real-time availability.

El Gouna Restaurant Finder — Find El Gouna restaurants by distance, cuisine, and dining type.

Zip Code Mapper — Draw polygons on a map to analyze which USA zip codes are enclosed.

PDF Diff — Show differences between two PDF files visually.

Markdown Cleaner — Clean AI-generated markdown for Google Docs compatibility.

Markdown → EPUB — Convert Markdown to a valid EPUB 3 file in your browser.

JPEG Compressor — Compress images with adjustable quality and compare file sizes.

Passport Photo Montage — Make a 3×2 montage from one photo. Print at 4×6 for six 2-inch passport photos.

DTF Print Processor — Halftone and colour-boost images for Direct to Film t-shirt printing.

Meeting Scheduler — Propose meeting slots and copy a message with one-click Outlook/Google calendar invite links.

Org Chart Builder — Upload an Excel file of employees and generate an org chart with SVG, PNG, and Mermaid exports.

Payment Plan Calculator — Generate NPV-based payment schedules for property purchases.

Twang — 1D dungeon crawler game. Tilt to move, shake to attack! (Mobile only)

Word Jumbler — Scramble words while keeping first and last letters intact.