Imprint
Who runs this site and how to reach them.
Operator
spheromino.com is an education-focused project run by Jakub Mráček, based in the Czech Republic.
Business details
Registered sole trader (OSVČ), Czech Republic.
IČO: 86719289
Registered address: J.V. Sládka 1548, Teplice, Czech Republic
Not registered for VAT.
Contact
Email: jakub.mracek@gmail.com
Paid products
The paid brochure is sold and delivered by Lemon Squeezy, which acts as the merchant of record. Lemon Squeezy handles the payment, invoicing and applicable taxes (including EU VAT). Your purchase receipt and billing details come from Lemon Squeezy.
Hosting
The site is hosted on Vercel and served as static pages.
Content
Unless noted otherwise, the puzzles, text and graphics on spheromino.com are the work of Jakub Mráček. The puzzle is an open project — free puzzles may be printed and shared for personal and educational use.
Last updated: 26 August 2026