--- title: "Blog | Once Books" description: "Guides, product notes and the thinking behind children’s books that look like one book: why AI illustrations drift, and how we keep a child recognisable." source: "https://www.oncebooks.com/blog" --- Blog # Notes from the workshop Guides, product notes and the thinking behind children’s books that look like one book: why AI illustrations drift, and how we keep a child recognisable. [Search all posts →](https://www.oncebooks.com/search) - [kdp24](https://www.oncebooks.com/blog/tag/kdp) - [low-content publishing13](https://www.oncebooks.com/blog/tag/low-content-publishing) - [print7](https://www.oncebooks.com/blog/tag/print) - [getting started6](https://www.oncebooks.com/blog/tag/getting-started) - [how it works6](https://www.oncebooks.com/blog/tag/how-it-works) - [word search6](https://www.oncebooks.com/blog/tag/word-search) - [engineering5](https://www.oncebooks.com/blog/tag/engineering) - [gifts4](https://www.oncebooks.com/blog/tag/gifts) - [planner4](https://www.oncebooks.com/blog/tag/planner) - [buying guide3](https://www.oncebooks.com/blog/tag/buying-guide) - [consistency3](https://www.oncebooks.com/blog/tag/consistency) - [crossword3](https://www.oncebooks.com/blog/tag/crossword) - [journal3](https://www.oncebooks.com/blog/tag/journal) - [keepsakes3](https://www.oncebooks.com/blog/tag/keepsakes) - [mazes3](https://www.oncebooks.com/blog/tag/mazes) - [niches3](https://www.oncebooks.com/blog/tag/niches) - [reading3](https://www.oncebooks.com/blog/tag/reading) - [sudoku3](https://www.oncebooks.com/blog/tag/sudoku) - [large print2](https://www.oncebooks.com/blog/tag/large-print) - [puzzle design2](https://www.oncebooks.com/blog/tag/puzzle-design) - [answer key1](https://www.oncebooks.com/blog/tag/answer-key) - [covers1](https://www.oncebooks.com/blog/tag/covers) - [guide1](https://www.oncebooks.com/blog/tag/guide) - [payments1](https://www.oncebooks.com/blog/tag/payments) - [personalisation1](https://www.oncebooks.com/blog/tag/personalisation) - [photos1](https://www.oncebooks.com/blog/tag/photos) - [pricing1](https://www.oncebooks.com/blog/tag/pricing) - [printables1](https://www.oncebooks.com/blog/tag/printables) - [printing1](https://www.oncebooks.com/blog/tag/printing) - [privacy1](https://www.oncebooks.com/blog/tag/privacy) - [representation1](https://www.oncebooks.com/blog/tag/representation) - [safety1](https://www.oncebooks.com/blog/tag/safety) - [self-publishing1](https://www.oncebooks.com/blog/tag/self-publishing) - [spatial puzzles1](https://www.oncebooks.com/blog/tag/spatial-puzzles) - [tools1](https://www.oncebooks.com/blog/tag/tools) - [wordsearch1](https://www.oncebooks.com/blog/tag/wordsearch) - [13 October 2026 · 6 min read](https://www.oncebooks.com/blog/word-search-books-for-kids-on-kdp) — Word search books for kids on KDP: what sells How to make a kids word search book that sells on Amazon KDP: big grids, short familiar words, no diagonals, bright themes. The choices that fit a child. - [kdp](https://www.oncebooks.com/blog/tag/kdp) - [wordsearch](https://www.oncebooks.com/blog/tag/wordsearch) - [low-content publishing](https://www.oncebooks.com/blog/tag/low-content-publishing) - [12 October 2026 · 8 min read](https://www.oncebooks.com/blog/how-to-self-publish-a-childrens-picture-book) — How to self-publish a children’s picture book Self-publishing a picture book, step by step: word count, page count, illustration costs, consistent characters, print-ready files, ISBNs and launch. - [self-publishing](https://www.oncebooks.com/blog/tag/self-publishing) - [kdp](https://www.oncebooks.com/blog/tag/kdp) - [getting started](https://www.oncebooks.com/blog/tag/getting-started) - [10 October 2026 · 7 min read](https://www.oncebooks.com/blog/sudoku-word-search-or-crossword) — Sudoku, word search or crossword: which to start with An honest comparison of the three big low-content puzzle formats for KDP: how each is made, who buys it, and where each one is harder to sell. - [kdp](https://www.oncebooks.com/blog/tag/kdp) - [low-content publishing](https://www.oncebooks.com/blog/tag/low-content-publishing) - [buying guide](https://www.oncebooks.com/blog/tag/buying-guide) - [9 October 2026 · 6 min read](https://www.oncebooks.com/blog/the-five-maze-shapes) — Five maze shapes, and what each one does to the solving Square, hexagonal, triangular, circular and picture-shaped mazes. How the grid changes the puzzle, which ages each suits, and what it costs to print. - [puzzle design](https://www.oncebooks.com/blog/tag/puzzle-design) - [mazes](https://www.oncebooks.com/blog/tag/mazes) - [printables](https://www.oncebooks.com/blog/tag/printables) - [8 October 2026 · 8 min read](https://www.oncebooks.com/blog/stripe-checkout-without-webhooks) — Stripe Checkout without webhooks: a pull-based design How we confirm Stripe Checkout payments with no webhook: session reuse, a unique checkout key, strict verification and a 10-minute reconciliation sweep. - [engineering](https://www.oncebooks.com/blog/tag/engineering) - [payments](https://www.oncebooks.com/blog/tag/payments) - [7 October 2026 · 7 min read](https://www.oncebooks.com/blog/what-makes-a-maze-hard) — What actually makes a maze hard (we measured it) Size is not difficulty. We graded a maze generator easy to evil, measured every page, and found one of our three difficulty signals ran backwards. - [puzzle design](https://www.oncebooks.com/blog/tag/puzzle-design) - [mazes](https://www.oncebooks.com/blog/tag/mazes) - [engineering](https://www.oncebooks.com/blog/tag/engineering) - [6 October 2026 · 7 min read](https://www.oncebooks.com/blog/kdp-cover-size-and-spine-width) — KDP spine width and cover size: the exact formula How to calculate KDP spine width and full-wrap cover size: the per-page paper multipliers, the bleed maths, three worked examples and the common mistakes. - [kdp](https://www.oncebooks.com/blog/tag/kdp) - [print](https://www.oncebooks.com/blog/tag/print) - [covers](https://www.oncebooks.com/blog/tag/covers) - [5 October 2026 · 8 min read](https://www.oncebooks.com/blog/picture-books-for-big-changes) — Picture books for big changes in a child's life A guide to picture books for a new sibling, starting school, fear of the dark and more: what each change feels like, and the books that help a child with it. - [reading](https://www.oncebooks.com/blog/tag/reading) - [getting started](https://www.oncebooks.com/blog/tag/getting-started) - [4 October 2026 · 8 min read](https://www.oncebooks.com/blog/how-to-make-and-sell-maze-books-on-kdp) — How to make and sell maze books on Amazon KDP A practical guide to maze books: picking a shape and an age, grading the book, provable answer keys, large print that means something, and the interior. - [kdp](https://www.oncebooks.com/blog/tag/kdp) - [mazes](https://www.oncebooks.com/blog/tag/mazes) - [low-content publishing](https://www.oncebooks.com/blog/tag/low-content-publishing) - [3 October 2026 · 6 min read](https://www.oncebooks.com/blog/kdp-sudoku-interior-specs) — KDP sudoku interior specs: trims, margins and solutions The trim sizes, margins, gutter, bleed and solutions layout a KDP sudoku interior needs to pass review, with the large-print grid numbers that sell. - [kdp](https://www.oncebooks.com/blog/tag/kdp) - [sudoku](https://www.oncebooks.com/blog/tag/sudoku) - [print](https://www.oncebooks.com/blog/tag/print) - [1 October 2026 · 8 min read](https://www.oncebooks.com/blog/how-we-guarantee-one-solution-sudoku) — How we make sure every sudoku has one solution How our sudoku generator works: fill a grid, remove clues in pairs, and re-solve after every removal so each board has one answer. Real code and timings. - [sudoku](https://www.oncebooks.com/blog/tag/sudoku) - [engineering](https://www.oncebooks.com/blog/tag/engineering) - [kdp](https://www.oncebooks.com/blog/tag/kdp) - [29 September 2026 · 9 min read](https://www.oncebooks.com/blog/kdp-paperback-publishing-checklist) — How to publish a paperback on KDP: the checklist The ordered checklist for publishing a paperback on Amazon KDP: trim, paper, page count, interior and cover PDFs, metadata, pricing, proof and review. - [kdp](https://www.oncebooks.com/blog/tag/kdp) - [print](https://www.oncebooks.com/blog/tag/print) - [getting started](https://www.oncebooks.com/blog/tag/getting-started) 1[2](https://www.oncebooks.com/blog/p/2)[3](https://www.oncebooks.com/blog/p/3)[4](https://www.oncebooks.com/blog/p/4)[Next →](https://www.oncebooks.com/blog/p/2) ## Keep reading - [Answers](https://www.oncebooks.com/answers) — One sharply-scoped question per page, cost, safety, timing, printing, answered in a couple of sentences before the detail. - [Glossary](https://www.oncebooks.com/glossary) — Plain definitions of the vocabulary: the Character Sheet, the Consistency Engine, style profiles, drift. - [Help centre](https://www.oncebooks.com/help) — Task-shaped instructions for making, printing and sharing a book once you have started one.