Academics
Solitaire Lab
A card game that is secretly a statistics lab — predict first, then test a solitaire rule change on 20-200 real Klondike deals played BOTH ways by a solver that never over-claims (won / lost / not sure yet). Read an honest at-least/at-most range and a 95% interval, see which deals the rules disagreed on, learn why a bigger search proves more wins of the same deals, and download a CSV for a science-fair chart. On-device, no account. Ages 9-14.
▶ Play it nowBuilt for sittings of about 20 minutes on the screen. That is our design budget, not a measurement.
Meet your mentor
Every Spark & Anvil app has a friendly mentor character that demonstrates, asks, and patiently scaffolds learning.
Mentored by Dealia
#1F7A7A Characters who teach
Meet the cast
Solitaire Lab's crew each embody one STATISTICS move — the crew IS the method. Twinnie deals every hand twice so the test is fair, Hedgeworth never says more than the data can (at least ... at most ...), Maybelle reminds you an unknown is a maybe, not a no, Bigsby knows more deals make the answer sharper, Lopsy watches the deals where the rules disagreed, Lanternby knows a bigger search is part of the result, Glassby knows an open deal's loss is a proof, Tiebelle calls overlapping ranges a tie, Seedwick keeps the seed so anyone can re-check, Tabitha keeps the raw rows, and Addison reasons from the rules before the data. Mentor Dealia asks what you predicted before you look.
Dealia
asks what you predicted BEFORE you look at the data
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Twinnie
Deals every hand twice - the same deals for both rules, so the test is fair
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Hedgeworth
Never says more than the data can - reports at least ... and at most ...
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Maybelle
Knows an unknown is a maybe, not a no - the search ran out of time
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Bigsby
Knows more deals make the answer sharper - the interval gets narrower
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Lopsy
Counts the deals where only ONE rule won - those odd pairs are the whole story
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Lanternby
Knows the measuring tool is part of the result - a bigger search proves more wins of the SAME deals
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Glassby
Knows FreeCell hides nothing, so a 'lost' there is a proof about the deal itself
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Tiebelle
Calls it a tie when the two ranges overlap - no winner the data cannot back
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Seedwick
Knows the same run seed rebuilds the same deals, so anyone can re-check your test
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Tabitha
Keeps one row per deal in the CSV so you can draw the chart yourself
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Addison
Knows a rule that only ADDS moves can never truly win less - reason before you run
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Browse all chapters → · What's distributed-narrative methodology? →
What's inside
Learning goal
A card game that is secretly a statistics lab — predict first, then test a solitaire rule change on 20-200 real Klondike deals played BOTH ways by a solver that never over-claims (won / lost / not sure yet). Read an honest at-least/at-most range and a 95% interval, see which deals the rules disagreed on, learn why a bigger search proves more wins of the same deals, and download a CSV for a science-fair chart. On-device, no account. Ages 9-14.
Mentored by Dealia — no data leaves the device.
How Solitaire Lab handles your kid's data
- ✅ All progress, settings, and AI-generated content stays on the device
- ✅ No analytics, no tracking, no third-party SDKs
- ✅ Free — no ads, no in-app purchases
- ✅ No personal information collected from children — in line with COPPA (updated by the 2026 FTC amendments)
- ✅ No chat with strangers — play-together rooms use a short code and preset emotes, never typed messages
For you, the grown-up
The grown-up side of Solitaire Lab on Spark & Whetstone, our free site for grown-ups: The Patience Club. They test which rules make patience winnable; you play one shared deal a week.