---
title: Donate
lead: Everything here is free; a donation is what keeps it that way.
figure: site-donate
button: Donate
link: https://donate.stripe.com/dRm3cu3XLfHj19e6WW5kk00
---

The crates, the papers, the demos and this site are open source and always will be. Nothing is behind a login, a paywall or an advert, and no page tracks the person reading it.

A donation buys the time to prove the next theorem and draw the next demo. Any amount helps, once or every month.