Krathong, Drawn · กระทง วาดด้วยคณิต

The Loy Krathong float drawn with math: folding a banana-leaf petal, rings of petals, why it floats and stays upright, where the Ping carries it, and Bangkok's count the morning after. English and Thai.

Live: https://motdang.net/sites/krathong/ · https://nanobotco.github.io/krathong/

• docs/krathong.js — folding a leaf across straight lines in 3D, rings of petals, Archimedes and the metacentre, a river fast in the middle.
• docs/app.js — every drawing on the page.
• tools/copy_text.py — every word, both languages; tools/build.py writes the pages (--motdang for the motdang.net copy).
• research/facts.md — the sourced notes behind the page.

Text CC BY 4.0, code MIT. Photographs keep their own licences, listed on the page.