NEW · PATTERN TRANSFORMATIONS
Rewrite Lab
Rewrite the tape to match the target. Each rule changes one matching group.
1. Choose a rule
2. Choose where to replace
1–4 rule · ← → position · Enter replace · U undo
Choose a rule, then a matching position.
Rules & controls
Replace one matching group with the right side of a rule. Everything outside that group stays in order. Rules can be reused; they only work from left to right. Never exceed eight symbols. Match the entire target within the move budget.
Click a rule, then a replacement. Keys 1–4 choose rules; Left/Right chooses a matching position; Enter applies it. Up/Down also changes rules. U undoes. No timer or lives. If a move leaves no solution within the budget, Undo freely.
Hint previews a shortest continuation from your current tape and remaining moves. It will report when you need to undo. Applying a hint is optional; viewing it counts as help.
36 original puzzles, each with one shortest solution. Deep rewrites require 10–12 moves and all four rules. Daily rotates this bank at 00:00 UTC; reload for a new date. Practice and Daily have separate progress during this page visit. Closing or refreshing resets it.
Rules & example: Rewrite Lab
- Replace one matching group with the right side of a rule. Everything outside that group stays in order.
- Rules can be reused, from left to right only. Keep at most eight symbols and match the entire target within the move budget.
- Choose a rule and a matching position. Keys 1–4 choose rules; Left/Right chooses a position; Enter applies; U undoes.
A quick example
With A → BB and BBB → C, start with AB. Replacing A gives BBB; replacing BBB then gives C in two moves.
Where to start
36 original puzzles, each with one shortest solution. Plan which patterns a change creates for the next rule. Deep rewrites need all four rules and 10–12 moves. Unlimited Undo; no timer or lives. Daily rotates the same bank. Progress lasts for this page visit.
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