Exponology.exponology.com

Every app here started as a frustration.

Exponology is my home for a growing collection of small apps — each one something I developed to help myself with a real, everyday problem. Some remove an annoyance that finally bugged me enough to fix it. A few are just for fun.

And every one of them was built with the help of an AI — or, more honestly, with the help of an AI agent I worked alongside, from the first sketch to the finished app.

Marketing and product development is the identification of a frustration.

A mentor told me that years ago, and it stuck. Find the thing that frustrates people — really find it, in real life — and you've found the product worth building. This site is dedicated to exactly that: overcoming frustration, one small app at a time. Except when an app is just for fun. Those are welcome here too.

Advice from a mentor — the rule behind every app here

The apps: born at the table — and the desk

Two of them started at the mah jongg table. Learning the game, I found the hardest part wasn't the rules — it was looking at the tiles in my hand and trying to pick which hand to go for, so the Finder and the Matcher do that matching for you. The third, CipherDesk, was born at the desk instead: the newspaper cryptogram, rebuilt for the screen. And the fourth, Prime Factor Finder, comes from a lifetime of teaching math — every number taken apart into its primes, by hand.

App No. 1

The Mah Jongg Hand Finder

Tell it what's in your rack. It tells you which hands are still within reach.

The card lists dozens of hands. Matching them against thirteen tiles in your head — while the Charleston moves and the table waits — is not easy. In fact, it's frustrating. So the Finder does the matching for you.

  • All 79 hands from the complete 2026 National Mah Jongg League card, each listed separately, just as the card lists them.
  • Search by what you're holding — suits, numbers, points, and the flowers, dragons, winds, pairs, pongs, kongs, and quints your hand needs.
  • Made for the middle of a game — when your first plan dies, re-search in seconds and pick a new hand before your next tile.
  • Runs on any phone or computer — nothing to install, nothing to sign up for.
Open the Hand Finder Learn More
App No. 2

The Mah Jongg Hand Matcher

Put in the tiles you're actually holding. It ranks the hands you could still make.

The Hand Finder searches the card by what you're looking for. The Matcher starts from the other end: enter your actual rack — 13 tiles, or 14 if you're East — and it lines your tiles up against all 79 hands on the 2026 National Mah Jongg League card, ranked by how close you are.

  • Three counts for every hand — how many of its tiles you Have, how many Jokers you're using, and how many you Don't Have yet, so the closest hands sort themselves to the top.
  • A gold star ★ next to the hand's name when it needs singles or pairs — the tiles a Joker can't stand in for, so you know before you commit.
  • A Random hand button deals you a practice rack to try it with — 14 tiles when East is checked, 13 otherwise.
  • Help built in — how to use the Matcher, and how to read the hands it shows you.
Open the Hand Matcher Learn More
App No. 3

CipherDesk

Newspaper cryptograms, desk edition — fill in the blanks, one letter at a time.

The kind of puzzle that used to sit beside the crossword: a short quote, encoded. Each letter stands for another letter, never itself — work out which is which, and the quote reveals itself.

  • The classic rule, kept simple — fill in the blanks over each cipher letter, with a substitution map that tracks every guess as you go.
  • Help when you want it — Hint, Check, Reset, and Undo, plus a timer, dark mode, and print, so a puzzle works on screen or on paper.
  • Pick by mood — categories Wisdom, Science, Leadership, Wit, History, Sports, and Comedy, plus All and Saved.
  • Bring your own, and keep favorites — paste a cryptogram, or type a solution and scramble it into a puzzle, then keep the ones you like in a Saved library.
CipherDesk app Learn More
App No. 4

Prime Factor Finder

Take any number apart into its prime factors — with your own taps.

Every whole number bigger than 1 is primes multiplied together — but a calculator just hands you the answer. Prime Factor Finder makes you do the building yourself: divide the number down, split it into a tree, group the primes, and watch every factor fall out.

  • Divide it down to its primes — any whole number from 2 to 1,000,000, with the answer shown plain and in exponent form, then checked by multiplying the factors back.
  • A prime factor tree — split any number into two factors and keep splitting until every branch ends in a prime.
  • Group the primes to make factors — multiply any bunch of them together and the product is a factor. Blocks lay numbers up to 100 out in rows, and a prime collection challenges you to find all 25 primes up to 100.
  • Reduce a fraction — line up the prime factors of the top and bottom and cancel the matching pairs: 84/90 walks down to 14/15, one pair at a time.
Open Prime Factor Finder Learn More

Built by a person. Built with an AI.

None of these apps would exist without two ingredients: a frustration I ran into myself, and an AI agent to help me build the fix. Here's how each one happens.

Spot the frustration

It starts in real life — at the mah jongg table, staring at a rack of tiles with no clear hand to chase. If a moment like that keeps repeating, it's a candidate.

Build it with an AI agent

I describe what I need and what "working" looks like. The AI helps design it, write it, and revise it — I steer, test, and decide what ships. It's a partnership, not a vending machine.

Use it myself

Every app here has to earn its place in my own life first — used at the table, in the middle of real games. If it doesn't actually help, it doesn't belong on this site.

A note from the founder

I'm an 80-year-old retiree, learning Mah Jongg and building the tools I wish I had. That's the whole story behind this site: when something frustrates me, I try to build the fix — with a little help from AI.

— Mike

The shelf is just getting started

The Hand Finder is the first app here, not the last. More are on the way — each one will start the same way this one did: with a frustration worth fixing, or an idea that's simply fun to build. When the next one is ready, it will take its place here.