Calculation method and privacy

Updated: 2026-09-07

What does this tool provide?

An independently developed interface, geometric formulas, cutting lists and examples, originally written in Traditional Chinese. The method uses one center square and four right isosceles triangles. It does not cover stitch-and-flip, foundation paper piecing or mixed seam allowances.

The formulas have been checked mathematically but not validated by sewing real fabric. Stretch, thickness, pressing and seam variation affect the result. Test one block before cutting a batch. For unexpected results, check units, finished/unfinished sizes and seam allowances. The full formulas and examples support step-by-step checking.

Are dimensions uploaded?

Calculation runs in your browser. There is no backend receiving dimensions, no login and no file upload. Analytics is off by default; Google Analytics loads only with consent. The guide's ad area is a placeholder with no ad-serving script.

The host processes connection data

Cloudflare provides HTTPS hosting. To deliver pages and protect the service, it processes IP addresses, requested URLs and browser connection data. This does not mean your entered dimensions are uploaded. See the Cloudflare Privacy Policy。

Advertising and analytics

Choose Allow analytics or No analytics below any page. With consent, we count page views, valid input interactions and copy success/failure, without dimensions, cutting results, clipboard contents or full error messages. Default samples and modified results are counted separately. A successful action does not prove a block was sewn. Analytics covers consenting visitors only; declining does not affect calculations or copying.

Google processes connection, browser/device and analytics cookie identifiers; this is not fully anonymous. Google signals, ad personalization and automatic form/interaction capture are disabled. URLs omit queries and referrers retain only the origin; no user account identifier is set. Analytics cookies last up to 60 days; the choice lasts 90 days. Withdraw below any page to stop future events and clear site analytics cookies; other open tabs in the same browser synchronize. Previously sent data is not automatically deleted from Google. See the Google Privacy Policy。

No ads are currently served. Before activation, Google's ad consent messages and this page will be updated. Analytics consent is not ad consent, and using the tool never requires clicking an ad.

Independent work

This site is not affiliated with or endorsed by quilting brands. The code, original Chinese explanations and geometric diagrams were independently created.