Who owns what

The original work in this repository and on https://lambdalab.in — the lesson text, the explanations and analogies, the interactive widgets and 3D scenes, the source code, the illustrations, the generated datasets and project reports, and the selection, sequencing and arrangement of all of it — is the copyright of the author.

It is protected automatically under the Copyright Act, 1957 and the Berne Convention. Neither registration nor this notice is required for that protection; this exists so that nobody can claim they did not know.

• Read, study and learn from the site. That is what it is for.
• Use it in your own teaching: show it in class, put a link to a lesson on a school website, blackboard or a student group, or set a page as homework.
• Quote a short passage, with attribution to LambdaLab and a link to the page, as fair dealing under section 52 of the Copyright Act permits.

No fee is charged for any of this, and no permission is needed.

• Copy the lessons, in whole or in part, onto another website, blog, app, PDF, printed book, coaching-centre handout or study material, whether or not the copy is sold and whether or not LambdaLab is credited.
• Copy, adapt or redistribute the source code, the widgets or the 3D scenes.
• Re-host the site or any part of it under another name.
• Present this work, or a paraphrase of it close enough to be recognisable, as your own.

Writing your own explanation of the same syllabus topic is not copying, and this notice does not try to reach it. Facts, the CBSE syllabus itself, and the ideas behind a lesson belong to everybody. The particular words, code and pictures here do not.

For permission beyond the section above, write to info@lambdalab.in. Reasonable requests from teachers and schools are usually granted.

• CBSE question papers, sample papers and marking schemes, reproduced on the site and stored under public/papers/, are the copyright of the Central Board of Secondary Education. They are reproduced for educational use. Nothing here claims any right over them.
• The CBSE curriculum and syllabus documents are likewise CBSE's.
• NCERT textbook content is the copyright of NCERT. The lessons here are written from the syllabus in the author's own words; the source books are not redistributed.
• Third-party software and data used by the site — including Next.js, React, three.js, Pyodide, shiki, framer-motion, Tailwind CSS and Natural Earth's boundary data — remain under their own licences, which are not affected by this notice and whose attribution requirements are to be kept intact.

The site and its code are provided "as is", without warranty of any kind. The lessons are checked carefully and every program on the site is run before it is published, but they are study material, not an official CBSE publication, and the author accepts no liability for any loss arising from their use.