Word Games
Ladder Climb
Lewis Carroll's 1879 word game. Turn one word into another by changing a single letter at a time — every rung must be a real word. Solo puzzles vs par + a live class race. The twist: the shortest ladder is a breadth-first shortest PATH through a graph of words, and the obvious "just fix the letters" move is a trap that dead-ends.
For Educators
Built for the classroom
Spelling and vocabulary fused with real graph theory. Every word is a node; an edge joins two words that differ by one letter; a "word ladder" is a PATH and the shortest ladder is a breadth-first SHORTEST PATH — the same algorithm behind maze solvers, GPS routing, and degrees-of-separation. Students discover the trap: the greedy "fix a wrong letter" heuristic can dead-end, because reaching some targets requires first changing a RIGHT letter to a wrong one. The game's par is computed by an independently-verified BFS over a clean, common, kid-safe lexicon of 3–5 letter words (no obscure or rude words). Beat par with no hints to earn the Doublets License and unseal the theorem. Invented by Lewis Carroll (Alice in Wonderland) in 1879 as "Doublets."
Grades 3+ · pick 3-, 4-, 5-, or 6-letter words (all open) · solo beats par, the live race gives the whole room the same start→target and ranks by fewest rungs. Par 3–6 per puzzle. (The 6-letter set is a curated, well-connected web of common words — 6-letter ladders are sparser, so the lexicon is built to keep every word reachable.)
Three ways to play
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Climb solo
Get a start word and a target. Change one letter at a time — tiles turn green as they match the goal. Reach the target at or under par (with no hints) to earn the Doublets License and unlock 📜 The Theorem.
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Host a Race
Open a room on the projector; a 4-letter code + QR + join link appear. The whole class gets the SAME start→target puzzle. Watch the leaderboard climb as students reach the target.
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Join on any device
Build your own ladder one rung at a time — the server checks every rung is a real word, one letter changed. Fewest rungs to the target wins. Undo a rung any time.
Run a live class in 5 steps
- Open the Race — choose 3-, 4-, 5-, or 6-letter words and the session length; share the 4-letter code / QR / link.
- Students join on any device; everyone gets the SAME start word and target.
- Each rung: change ONE letter to make a new real word, climbing toward the target. Fewest rungs wins.
- Ask the room mid-race: did anyone get STUCK fixing letters? That dead-end is the greedy trap.
- At the end, reveal a model shortest ladder — then send the fast finishers to the Dojo to meet breadth-first search.
Tip: host on a laptop or projector (the big screen shows the code, QR and leaderboard); students join on their phones or laptops.
